'CLEA1
WATER POLLUTION CONTROL RESEARCH SERIES
14010FMH12/70
Treatment of Acid Mine Drainage
by Ozone Oxidation
ENVIRONMENTAL PROTECTION AGENCY • WATER QUALITY OFFICE
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WATER POLLUTION CONTROL RESEARCH SERIES
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20242.
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Treatment of Acid Mine Drainage by Ozone Oxidation
Department of Applied Science
Brookhaven National Laboratory, Associated Universities, Inc,
U.S. Atomic Energy Commission
Upton, New York 11973
for the
ENVIRONMENTAL PROTECTION AGENCY
Contract No. 14-12-838
Project No. 14010 FMH
December 1970
For sale by the Superintendent of Documents, U.S. Government Printing Office
Washington, D.C., 20402 - Price $1
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EPA Review Notice
This report has been reviewed by the Environmental
Protection Agency and approved for publication.
Approval does not signify that the contents neces-
sarily reflect the views and policies of the Environ'
mental Protection Agency, nor does mention of trade
names or commercial products constitute endorsement
or recommendation for use.
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ABSTRACT
An engineering design and economic study to evaluate
the feasibility of ozone oxidation and limestone neutral-
ization of Acid Mine Drainage (AMD) was performed. The
study concludes that an ozone process is feasible, com-
pares economically with existing processes, and offers
potential advantages in process control, reduced neutral-
ization costs, and simplified AMD sludge handling and
disposal. Ozone production by electric discharge and
radiation processes are compared both for on-site and
central plant installations utilizing ozone shipping and
storage facilities. A central chemonuclear ozone produc-
tion plant with a distribution system is found to be most
economical, followed by electric discharge central and on-
site plants. Design and construction of a mobile pilot
plant which employs electric discharge ozonizers is recom-
mended for field trials of the process.
This report was prepared in fulfillment of Contract
No. 14-12-838 between the Federal Water Quality Adminis-
tration and Brookhaven National Laboratory.
Key Words: Mine drainage, ozone treatment, treatment costs
neutralization, limestone, oxidation, ferrous
iron, ferric iron.
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CONTENTS
Page
Abstract
List of Figures
List of Tables
1. Introduction 1
2. Summary and Conclusions 5
3. Recommendations 7
4. AMD Treatment Process Design 9
5. Ozone Production Methods 17
5.1 General Considerations 17
5.2 Electric Discharge Synthesis 19
5.3 Radiation and Chemonuclear Synthesis 20
5.4 New Methods 24
5.5 Process Descriptions 25
5.5.1 Isotopic Process 25
5.5.2 Electric Discharge Process 25
5.5.3 Chemonuclear Process 25
6. Economic Analysis 31
6.1 On-Site Plants 31
6.1.1 Isotopic Process 31
6.1.2 Electric Discharge Process 41
6.2 Central Ozone Production Plants 49
6.2.1 Ozone Shipping and Storage 49
6.2.2 Chemonuclear Process and 52
Comparison with Electric
Discharge Process
6.3 AMD Treatment Plant 65
6.4 Comparison with Present Methods 79
111
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CONTENTS (Cont'd)
Page
7. Discussion 81
Acknowledgement 83
References 84
Appendix A-l
IV
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LIST OF FIGURES
No. Page
1 AMD Oxidation and Neutralization Process
System 12
2 Brookhaven Chemonuclear In-pile Research
Loop 22
3 History of Run No. 3 23
4 Ozone Generation Using Isotopic Sources 26
5 Electric Discharge Ozone Process for Water
Treatment 27
6 Chemonuclear Ozone Generation and Purifica-
tion for Water Treatment 28
7 Gamma-ray Energy Absorption in 02 vs Path
Length 33
8 Ozone Yield vs Oxygen Pressure 34
9 Investment Cost for Ozone Using Isotopic
Radiation 36
10 Cesium-137 Ozone Generator, Production Cost
vs Capacity 37
11 Cobalt-60 Ozone Generator, Production Cost
vs Capacity 38
12 Isotopic Source Ozonizers, Cost of AMD Ozona-
tion at Varying Stream Flows 39
13 Electric Discharge Ozonizers, Production Cost
vs Capacity 45
14 Electric Discharge Ozonizers, Cost of AMD
Ozonation-Once-Through Air Feed 46
15 Electric Discharge Ozonizers, Cost of AMD
Ozonation-Oxygen Feed and Recycle 47
16 Ozone Storage and Distribution System 50
17 Distribution of Draining Coal Mines in Penn-
sylvania Counties 51
18 Production Cost of Ozone, Conventional vs
Chemonuclear Processes 53
19 Electric Discharge vs Chemonuclear AMD Treat-
ment Plant Costs Using Ozone, Large Central
Plants 54
20 Total AMD Treatment Cost Using Ozone-Electric
Discharge Ozonizers-On-site Generation 71
21 Total AMD Treatment Cost Using Electric
Discharge Ozone-Central Plant Ozone Genera-
tion, Shipped to AMD Site 72
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LIST OF FIGURES, cont'd.
No. Page
22 Total AMD Treatment Cost Using Chemonuclear
Ozone, Central Plant Ozone Generation,Shipped
to AMD Site 73
23 Total Plant Investment for AMD Treatment
Using On-site Electric Discharge Ozone 75
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LIST OF TABLES
No. Pag(
1 Typical AMD Stream Compositions 10
2 AMD Plant Material Balance 13
3 Ozone Requirements for AMD Streams 15
4 Energy Requirements for Ozone Synthesis 18
5 Characteristics of BNL Gamma Sources 32
6 Ozone Investment Costs, On-site Generation,
Once-Through Air Feed 42
7 Ozone Production Costs, On-site Generation,
Once-Through Air Feed 42
8 Ozone Investment Costs, On-site Generation,
Recycled Oxygen Feed 43
9 Ozone Production Costs, On-site Generation,
Recycled Oxygen Feed 43
10 Cost of Purchased Oxygen Gas 44
11 Chemonuclear Ozone - Total Production Cost 55
12 Chemonuclear Ozone - Investment Cost 56
13 Electric Discharge Production Cost 57
14 Electric Discharge Ozone Investment Cost 57
15 Chemonuclear Ozone System Power Requirements 58
16 Electric Discharge Ozone System Power Re-
quirements 59
17 Chemonuclear Ozone Energy Requirements 59
18 Electric Discharge Ozone Energy Requirements 60
19 Storage and Distribution System 63
20 AMD Plant Cost 66
21 AMD Treatment Plant Operating Cost 67
22 AMD Treatment Total Operating Cost, Ozone
Generated On-site, Electric Discharge 68
23 Ozone Generated in 40 Ton/Day Central Plants 69
24 Ozone Generated in 200 Ton/Day Central
Plants 70
25 Total Investment Costs for AMD Treatment
Using On-site Ozone with Recycled Oxygen Feed 74
26 Comparison of AMD Total Treatment Costs 76
27 Cost Breakdown for Total AMD Treatment of
Pennsylvania AMD Streams 78
28 Cost of Conventional AMD Treatment 80
VII
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1. INTRODUCTION
The problem created by acid mine drainage (AMD) has
been reported in great detail in recent years.(1/2) The
formation of "yellowboy" in streams and the effect of
mine drainage on water quality in mining areas has prompted
a considerable research and development effort in regard to
the treatment of acid mine drainage.
Treatment studies have, in general, considered the
neutralization of the mine drainage using various low cost
materials such as limestone,(39'4°) lime and sodium carb-
onate, followed by or concurrent with an aeration step to
oxidize iron from the ferrous to the ferric state. The
resultant precipitate of iron and various neutralization
products are then separated and removed from the bulk flow
of treated water.
The work being done in the development of water treat-
ment techniques has served to point up the wide range of
problems associated with AMD treatment.(3/4) ^ir oxidation
is a relatively slow process, dependent on the pH of the
water and the rate of aeration. Precipitate quality can be
quite poor depending on several factors including the type
of neutralizer used, whether sludge recycling is practicable
and the point at which process oxidation occurs. High alka-
linity is required to get the most favorable reaction rates
but excessive neutralizer use adds to the sludge handling
problems and presents a risk of discharging highly alkaline
waters to streams. In general, the wide variability in AMD
composition has led to a number of treatment methods which
are adequate for specific mine and mine water conditions
but which may not be capable of being applied elsewhere
without some degree of modification.
In this study, ozone is evaluated as an oxidizing agent
for the oxidation of the iron in AMD from the ferrous to the
ferric state.
The scope of the study includes a detailed engineering
design and cost estimate for the production and supply of
ozone, and evaluation of the entire AMD oxidation-neutrali-
zation treatment process. The ozone production and distri-
bution processes investigated are as follows:
-1-
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1. The synthesis of ozone by isotopic radiation
using ^^Co and 13?cs gamma radiation sources.
2. The synthesis of ozone by the corona electric
discharge process.
3. The synthesis of ozone by the chemonuclear
reactor process.
4. The problems of shipping ozone from a central
production plant are examined, and shipping
costs to mine drainage sites are estimated.
The use of ozone for AMD treatment has been investi-
gated by Rozelle, et al (6) an(j a number of favorable
conclusions regarding its application can be drawn from
that work.
A comparison of the use of oxygen and ozone for
oxidation of Fe+2 to Fe+3 is made by Rozelle through
the use of the following equations. The sequence for
the reaction with oxygen in aqueous solution^, 38) is
as follows:
(1) Hydrolysis
+2 +
Fe + 2H O & Fe (OH) + 2H
& ^
(2) Neutralization
2H+ + 20H~ *± 2H20
+3
(3) Oxidation of Fe
2Fe+2 + %02 + 40H~ + H20 - 2Fe(OH)
Hydrolysis curves for the complete neutralization of
the combined acid in the ferrous iron system show that
sufficient alkaline reagent must be added to bring the pH
to a value of 10.(6)
On the other hand, using ozone for oxidation in low
pH solutions, the following system of equations is pre-
sented.
-2-
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(1) Oxidation
2Fe+2 + 0 + 2H+ *± 2Fe+
(2) Hydrolysis
Fe+ + 3H 0 ^ Fe (OH) + 3H+
(3) Neutralization
3H+ + 30H~ ^ 3H O
^
The hydrolysis reaction involves a number of immed-
iate species and their formation is described by Rozelle,
et al as being similar to the following:
(1) Fe+ + HO tf Fe(OH)+2 + H+
*£
(2) 2Fe+3 + 2H20 *± Fe2 (OH) 2+4 + 2H+
(3) Fe(OH)+2 + HO *± Fe (OH) + + H+
£ ^
(4) Fe(OH) + + H20 ^ Fe (OH) _ + H+
The net combined acid released in the oxidation and
hydrolysis is the same for either oxygen or ozone treatment.
Neutralization of the combined acid associated with oxida-
tion of Fe+2 by ozone can be accomplished at pH values of
approximately 3. ' ' However, hydrolysis takes place at a
rapid rate at a pH of 4 or above. Consequently, neutralizer
quantities are expected to be lower since only enough neutra-
lizing agent need be added, beyond that required to handle
the combined acid, to bring the water to a pH where precipi-
tate quality and rate of coagulation is best. This value is
in the pH 5-7 range. '5)
Increased reaction rates and better precipitate qual-
ity will minimize holdup times and the need for solids-
liquid separating equipment. Precipitation of Fe+3 below
the isoelectric point (pH~ 7) results in a dense precipi-
tate of 15-20% solids, (^) while precipitation of Fe+2
above this point yields a voluminous flocculant precipi-
tate. The effectiveness of ozone as an oxidizing agent
is also expected to extend to removal of other metal ions
such as Mn+2 and Al+3 in the acid mine drainage waters.
-3-
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Steinberg, et al, in a series of papers, dis-
cussed the utilization of high energy radiation in
treating acid mine drainage. This work included a study
of the use of radiation in conjunction with neutraliza-
tion using mechanically agitated limestone. The conclu-
sions reached in this study point out the effectiveness
of the limestone treatment in terms of the rate of removal
of iron and precipitate quality. The use of lime in con-
junction with limestone as adopted by some investigators(1)
would seem to be unnecessary and undesirable when viewed
in the context of the work of Rozelle and Steinberg. Using
ozone to first oxidize the ferrous iron would allow pre-
cipitation and removal of iron to occur at low pH values.
Thus, the buffering action of CC>2 resulting from the use
of limestone would not be a limiting factor in the process
and would, in fact, eliminate the possibility of over-
neutralization and the need for fine control which the
use of lime entails.
-4-
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2. SUMMARY AND CONCLUSIONS
The economics of using ozone for treatment of Acid
Mine Drainage (AMD) are evaluated. The treatment con-
sists of rapid oxidation of ferrous to ferric iron with
ozone and neutralization with limestone. Ozone produc-
tion is considered using electrical discharge, isotopic
radiation and chemonuclear methods. Ozone production
facilities are evaluated both at the usage point and
for large central plants in conjunction with a distribu-
tion system. Designs for these systems are outlined,
and appear feasible. The ranges used in the study are
AMD flows from 250,000 to 6,000,000 gal. per day con-
taining Fe+2 concentrations varying from 50 to 1,000 ppm.
In general, both chemonuclear and electric discharge
central ozone production plants with a distribution sys-
tem offer clear economic advantages over on-site plants
except for AMD streams with low Fe++ content (~50 ppm)
and low flows (250,000 gpd). The treatment costs vary
with Fe content and AMD flow. These costs are esti-
mated to range from 9-13£ per 1,000 gal. AMD treated at
50 ppm Fe over the entire flow regime studied. At 300
ppm Fe+2, the treatment costs are 18-34C per 1,000 gal.,
and at 1,000 ppm the cost range increases to 40-78C per
1000 gal.
The lowest cost in each of the above ranges applies
to central plants with distribution systems, high AMD
flow rates, and ozone production via the chemonuclear
process. The highest cost in each range is for on-site
electric discharge ozone at low flow rates.
The isotopic radiation process is less economical
but might be useful for very low flow and low Fe+2 content
streams.
Ozone oxidation with limestone neutralization com-
petes favorably with the presently used air oxidation
and lime neutralization system on an economic basis.
Conventional methods have been estimated to range from
$0.10-$1.30 per 1000 gal.; the present study estimates
-5-
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that the ozone-limestone process ranges from $0.09-$0.78.
An estimate for a specific case of 1,000,000 gpd and
Fe+2 concentration of 150 ppm results in a treatment
cost of $0.17 per 1000 gal. using the air-lime method.
The ozone-limestone process can treat the same stream
for $0.13-$0.16. The investment cost is $350,000 for
the conventional air-oxidation and lime process, compared
with an estimate of $280,000 for an on-site electric dis-
charge ozone-limestone facility. The investment cost
using ozone from a central plant, and including on-site
ozone storage equipment, would be $184,000.
The investment cost necessary to treat the entire
AMD of southwestern Pennsylvania, estimated at 486,000,000
gal. per day, would be $182,000,000, based on the use of
a 200-ton per day central chemonuclear ozone plant. The
investment cost includes ozone storage and shipment fac-
ilities and AMD treatment equipment at each of the approx-
imately 2160 sites in the region. Each site is assumed
capable of handling an average flow of 250,000 gal. per
day. A central electric discharge plant would require an
investment of about $191,000,000. Since the chemonuclear
system requires additional development, the initial plant
cost for both chemonuclear and electric discharge ozone
are roughly comparable; however, the chemonuclear plant
operating costs are lower.
The study concludes that the ozone-limestone system
offers the potential of simplified process control, higher
plant throughput, removal of additional pollutants from
AMD, and reduced sludge-handling requirements at costs
equal to or less than those obtained using present tech-
niques .
-6-
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3. RECOMMENDATIONS
It is recommended that a mobile pilot plant be
built which incorporates an electric discharge ozonizer
system for trials at AMD sites which have varying Fe+2
contents and flows. This will permit evaluation of the
ozone-limestone system under actual field conditions,
and will also provide data for large-scale design of
treatment plants. The chemonuclear system has economic
advantages in the long-term picture, but will require
additional expenditures associated with its development.
Since the electric discharge system is presently avail-
able and appears economic, it is recommended that pres-
ent emphasis be placed on development of AMD cleanup
using the electric discharge method for ozone supply
and on-site plants. New methods of ozone production,
which may offer even greater economic advantages, should
also be explored.
It is also recommended that, because of the economic
incentives offered by central ozone generating plants
with distribution systems, effort should be expended in
the area of ozone storage and shipment technology.
-7-
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4. AMD TREATMENT PROCESS DESIGN
Because acid mine waters range widely in flowrate
and composition, three flows and ferrous iron composi-
tions were selected which generally encompass the- con-
ditions existing at typical AMD sites. The AMD flow
rates chosen are 6,000,000, 1,000,000, and 250,000
gallons per day, containing ferrous iron contents of
1000, 300, and 50 parts per million. Apart from the
ozone treatment vessel, the remaining plant components
are based on those used or tested in various AMD treat-
ment plants or plant studies. A basic plant design was
considered here for two reasons. First and most signif-
icant is the belief that oxidation of Fe+2 to Fe+^ with
ozone at low pH values will improve later neutralization
and precipitation steps to an extent not experienced in
other studies. The second consideration is the recogni-
tion that the variety of mine waters and sources that
are encountered make it impractical to cover each case.
By presenting a plant design which is applicable to a
widely varying flow and composition regime, any addi-
tional complications brought about by use in a specific
location can be factored in by the designer with a mini-
mum of difficulty. The neutralization process detailed
here was based on neutralization of the acidity generated
in the oxidation and hydrolysis reactions with an AMD
having an initial pH of 2.5.
The acidity resulting from the oxidation and hydrol-
ysis reactions is referred to as "combined acid." The
acidity associated with the initial pH of the water is
considered to be "free acid." Total acidity is the sum
of the combined and free acid values. In all cases,
these have been described in terms of the quantity of
CaC03 necessary to react with the acid present.
Ranges and average values for some typical AMD stream
compositions are shown in Table 1.
-9-
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TABLE 1
TYPICAL AND STREAM COMPOSITIONS
All values in mg/1
Range* Average*
PH 2.5-3.2 3.1
Total acid (as CaCO3) 86-4080 1130
Total Fe 1.3-815 280
SO 290-10,000 3080
Mn 4.4-38 16
Ca 4-440 220
Mg 0-404 154
Al 24-900 223
(37)
*Based on 5 AMD Sites
+2
The values of Fe and total acidity used for the
study are summarized below. For simplicity, any acid
resulting from the hydrolysis of metal ions other than
iron has been ignored.
+2
Fe conc.-ppm pH Total Acid (mg/1 CaCO )
1000 2.5 19.00
300 2.5 650
50 2.5 200
The AMD treatment plant is designed to meet the
Pennsylvania legal requirements for discharge of 7 ppm
maximum iron, and pH between 6 and 9. Ozone treatment
and limestone neutralization can permit treated water to
be discharged at pH 6-7, meeting state water quality
standards. Laboratory tests indicate that the iron
content can be reduced to less than 1 ppm.
-10-
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The ozone process treatment plant and ozone treat-
ment methods are described in the following sections.
Fig. 1 is a schematic of the process and Table 2 is a
material balance for all corresponding AMD stream condi-
tions of iron content and flow rate.
The three nominal flow rates and ferrous iron con-
centrations used to size the treatment plant have been
described. It is assumed as well that the flow of mine
drainage will vary to some extent through the day. Rec-
ognizing the desirability of a constant plant throughput,
a holding pond with a controlled outlet flow rate has
been provided at the head end of the plant. For plants
with a low flow rate, the holding pond could be used for
storage of water during the night shift, thereby reducing
plant operation to a one or two shift basis.
This process permits the use of limestone for neu-
tralization, since all the iron is in the ferric state
after ozone treatment and precipitation will occur at
pH 5-7. Limestone is cheap, readily available and, in
conjunction with an ozone process, is an effective neu-
tralizer. A limestone slurry is produced by loading a
tumbling mill with bulk limestone and providing a flow
of water to give the slurry mix desired. A slurry with
particle sizes less than 400 mesh is produced. Other-
wise a slurry can be produced by mixing limestone powder
and water in a mixing tank. Over-all costs would not be
significantly different and the method chosen would
depend on local preference. For this study, limestone
containing 75% CaC03 was used as a basis for sizing equip-
ment. Based on this CaCO content, a limestone quantity
in slight excess of the stoichiometric amount was chosen
as a reference point for this study-
Ozone is produced as a 1.7 weight per cent mixture
(1% by volume) in a gaseous oxygen stream. It is sup-
plied to the oxidizing contactor, and after reacting
with the AMD, is recycled to the ozone production unit.
AMD from the holding pond is fed to the oxidation
vessel after an initial pH adjustment with limestone
slurry. The pH adjustment is included, subject to exper-
imental verification, on the basis of information
-11-
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NJ
I
(7) OXYGEN RECYCLE
DEMISTER
OXIDIZING
VESSEL
AMD
REGULATED FLOW
7
(I ) ACID MINE DRAINAGE
HOLDING POND
SLURRY MILL
£^5) AMD pH
ADJUSTED
ni i i TD
TO 3.0
(4) LIMESTONE SLURRY
(6) \.7\ 03 IN
(8) OXIDIZED AMD
(9) AMD pH RANGE 6-7
STREAM MIXER
LIMESTONE (3)
(75% Co C03)
TREATED WATER
SLURRY RECYCLE
(10)
SETTLING POND
(II) TREATED AMD
(\2f- SLUDGE
AMD OXIDATION S NEUTRALIZATION PROCESS SYSTEM
FIGURE 1
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TABLE 2
AMD PLANT MATERIAL BALANCE
raa?
1
2
3
4
5
6
7
8
9
(1) (2)
AMD Fe 1*
gpd pjm/T/d
6xl06 1000/25
300/7.5
50/1.3
IxlO6 1000/4
300/1.2
50/0.2
JjXlO6 1000/1
300/0.3
50/0'. 05
(3)
CdS04
T/d
63
21
6
10
3.5
1.0
2.5
0.9
0.25
(4)
Slurry
X3xl05
45xl04
1/txlO4
LSxlO4
6200
2230
5200
1740
500
(5)
Adj AMD
6.1X106
6xl06
IxlO6
Jj X 106
(6)
03+02
T/d
736
224
36
123
36
6
30
9
2
(7)
02
Recycle
T/d
730
221
35
122
35
6
29
9
2
T/d =
(8) (9)
Oxid. Neutral
AMD AMD
6.1x10°
6xl06
6xl06
IxlO6
IxlO6
IxlO6
JspclO6
>5Xl06
ijxlO6
tons per day
(10)
water
recycle
1.3X105
4.5xl04
1.4xl04
l.SxlO6
6200
2230
5200
1740
500
(11)
Treated AMD
flow
gpd
6xl06
IxlO6
SjXlO6
Sol CaSO4
T/d
50
21
6
9
3.6
1.0
2
0.9
0.3
(12)
Sludcre
CaSO4
T/d
13
-
-
1
-
-
0.5
-
-
Fe(OH)3
T/d
48
14.4
2.4
7.9
2.4
0.4
1.9
0.6
0.1
Misc.
T/d
16
5
1.5
2.6
0.9
0.1
0.5
0.2
0.1
(13)
O3 Loss
with (8)
T/d
0.18
0.18
0.18
0.03
0.03
0.03
0.007
0.007
0.007
(14)
°3
in (6)
T/d
126
3.8
0.6
2.1
0.6
0.1
0.5
0.15
0.03
(15)
°2
in (6)
T/d
723
220
35
121
35
6
29
9
2
(16)
°2
loss
T/d
1.25
1.25
1.25
0.21
0.21
0.21
0.05
0.05
0.05
-------
suggesting that the oxidation might be enhanced by opera-
tion with the pH at or slightly above a value of 3. It
is known that hydrolysis of Fe+3 occurs above a pH of 3
and that some cations, possibly those present in lime-
stone, have a catalytic effect on the oxidation process.
In addition, Rozelle, et al^6^ found sulfate in measure-
able amounts in precipitates formed in low pH (<2.7) sol-
utions but only traces of sulfate in precipitates from
solutions of pH 3.5. The pH adjustment to pH 3.5 thus
would also prevent premature sulfate precipitation in
the oxidation vessels.
A turbine type mixer has been used in the oxidizing
vessel for purposes of this study- This type of contact-
ing device should be more than sufficient for the AMD-
ozone system and provides a conservative design in terms
of equipment and power costs. Actually, values for con-
tacting efficiency were chosen using Roselle ' s data. ^ '
These were based upon studies using simple bubbler type
contacting devices in which contact times and areas were
small. Again, the data provides conservative values for
use in this study. The specific nature of previous work
in gas-liquid contacting studies makes a more rigorous
application and scale-up of the data to the AMD-ozone
system difficult. Experimental work to verify the appli-
cability of available correlations is necessary- (&• **• ^
Following oxidation of the ferrous iron, limestone
slurry is added to the stream from the oxidizing vessel,
and turbulence is used to provide mixing. In the absence
of ferrous ion, precipitation should be relatively rapid
and in a form favorable to rapid settling in the final
settling pond. Results of neutralization tests with
limestone slurry indicate that neutralization should be
substantially complete by the time the material reaches
the settling
Ozone requirements for the various cases on which
the study is based are shown in Table 3.
-14-
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TABLE 3
OZONE REQUIREMENTS FOR AMD STREAMS
LB/DAY OZONE
AMD Stream Flow-Gal . /Day
_i_ _i_
Fe Conc.-ppm 0.25x10 1.0x10 6.0x10
50 52 208 1,248
300 312 1,248 7,488
1,000 1,040 4,160 24,960
The ozone requirements are based on the stoichiom-
etry of the oxidation reaction:
2Fe+ + O + 2H+ ^ 2Fe+ + HO + 0
O £ £
+2
One mole of ozone oxidizes 2 moles of Fe . On a mass
i O
basis, 0.43 Ib of ozone oxidizes 1 Ib of Fe . At the
86% utilization efficiency which Rozelle(^) obtained in
his work, the ozone uptake for oxidation becomes:
0.5 Ib 03/lb Fe+2
This can also be expressed as:
+2
0.417 Ib O /100 ppm Fe /1000 gal./day AMD
-15-
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5. OZONE PRODUCTION METHODS
5.1 General Considerations
Ozone is produced by the introduction of energy
into an oxygen-containing stream. The formation reac-
tion is endothermic. The ozone formed can also undergo
thermal decomposition, thus accounting for the rela-
tively low efficiency and the large energy requirement
for its production. High energy (~5eV) is required to
break the oxygen bond to form an 0 atom, which then
combines with an 02 molecule to yield an O^ molecule.
The energy necessary can be obtained by photochemical
radiation, nuclear radiation, or electrical discharge.
The over-all reaction is:
3/2 02 (g) - 03(g)
and the enthalpy of reaction is:
AH298 2 = 34 Kcal/mole
The minimum thermodynamic energy requirement is
thus 34 Kcal of energy to form a mole of ozone. As a
comparison, one can consider the practical present-day
achievable efficiencies, shown in Table 4. Electrical
discharge ozonizers operating with oxygen have energy
requirements ranging from 3.75 to 5.0 kw-hr./lb ozone,
which is equivalent to a G-value of 6.8 to 5.1. G-values
ranging from 10-15 can be achieved using high energy
radiation, offering a potential doubling in the effic-
iency of ozone production. G-value is a measure of
chemical production for a given energy input, and is
defined as the number of molecules of product resulting
from the input of 100 eV of energy into the reactant.
Table 4 shows that the more efficient methods are
isotopic sources, which generate gamma radiation, chemo-
nuclear fission fragment sources, and electric discharge
ozonizers. These three methods were chose for economic
evaluation.
-17-
-------
TABLE 4
ENERGY REQUIR3MENTS FOR OZONE SYNTHESIS
Energy Yield - Kw. Hr/lb Ozone % Over-all
Thermal Energy Thermal
Method Electrical Equivalent Efficiency
Electric Discharge in Oxygen 3.75 11.2 3.3
Electric Discharge in Air 7.25 21.8 1.7
(2
Chemonuclear (Fission Fragment) — 4.8 7.7
Isotopic Sources (Gamma) — 3.4 10.9
Photochemical 18.0 54.0 0.7
Theoretical Thermodynamic -- 0.37 100.0
33% Power Conversion Efficiency, Thermal to Electrical
35% Energy Deposition Efficiency
50% Energy Deposition Efficiency
-18-
-------
5.2 Electric Discharge Synthesis
Ozone is presently produced almost entirely by the
electric discharge process. The apparatus(31) designed
to produce ozone by this method is called an ozonizer,
and consists of a pair of electrodes separated by glass
insulators and an air space. When a high voltage
(50,000 v) alternating current is applied, the air
space is filled with a diffused glow (a corona dis-
charge) . The insulators prevent sparking or arcing,
and the alternating current provides polarity reversal,
permitting accumulation and discharge of electrons during
each half cycle. When air or oxygen is passed through
the air space, the electron release provides the energy
necessary to produce ozone. Since more than 90% of the
applied energy is dissipated as heat, cooling must be
provided for the electrodes and the ozone must be removed
rapidly to prevent thermal decomposition.
For a given energy input, twice as much ozone can be
generated from an oxygen stream as from an air feed. The
oxygen must be recycled since it contains only 1% by
volume of ozone, and it is not economic to discard it.
Therefore, recycling pumps and driers are necessary for
an oxygen feed system.
The electric discharge method has resulted in rather
limited usage of ozone, since power consumption and in-
vestment costs are high, and the advantages of large
scale are difficult to achieve for two reasons. First,
because electric discharge units are, at best, rather
small capacity individual devices, a large multiplicity
of the machines is required. Second is the problem of
ozone shipment. Ozone is presently shipped(12) in small
quantities; however, there seems to be no technical
reason to prevent the implementation of the technology
to large-scale shipments. It appears that the incentive
to do so is lacking, possibly because the economics of
large shipments has not been studied. For these reasons,
ozone production economics in this report were looked at
from two points of view: first, production of ozone at
the usage point, with production quantities matched to
the requirement of the site, and second, ozone generation
at a large central facility with subsequent shipments to
usage points.
-19-
-------
5.3 Radiation and Chemonuclear Synthesis
The radiation chemistry of ozone has been studied
since the early work of Lind.^13^ The experiments have
been mainly performed in static systems, at low pres-
sures and at low temperatures. In liquid oxygen under
static conditions in glass apparatus, an initial G
value for ozone formation of 6 and high concentrations
up to 6% by weight is reported by Wall and Brown, d )
In gaseous oxygen in a static steel system at a temp-
erature of -78°C, a G(03) value of 9 is reported by
Kircher. (15) ^t -78°C in a static glass system at 1 atm
Johnson and Warman report an initial G(O3) value of
12. 8 (16) In experiments by Sears and Sutherland in
glass capsules in the gas phase at 1 atm 02 in a Co60
field, initial G(03) values up to 10.5 were found.
In capsule experiments with fission fragments in an in-
pile experiment, at a temperature between R.T. and -78°C,
a minimum G(03) value of 6.9 was measured and a concen-
tration up to 0.5% was obtained . (I?) In flow systems,
investigations have been made with air at room tempera-
ture and 1 atm pressure mainly for purposes of investi-
gating the hazards of ozone formation associated with
radiation processes for sterilization of medical sup-
plies and food preservation.'!8'-^) In a closed glass
system an O3 concentration up to 18.5 ppm was measured
and a G(03) value up to 4.0 can be estimated from the
work by Kertesz and Parsons . (18) A study by Shah and
Maxie (20) in a flowing air system, constructed of glass
at atmospheric pressure using gamma radiation indicated
a G(O3) value of 11 at 03 concentrations of 1.7 ppm.
Flow experiments in a high pressure steel system in a
Co60 gamma field at 68 atm and above with air at room
temperature indicated a G(03) of 4.7.(21) Recent ex-
periments with oxygen at pressures up to 200 atm and
-60°C in a stainless steel system in a radiation field
gave a G value of 10. 5. (22)
A G value of 13.8 was determined in pulse radioly-
sis experiments (23) with high energy electrons in oxygen
at 1 atm and high dose rates.
For purposes of studying fission fragment chemistry
in a flow system and in addition fuel behavior and
product contamination problems, an in-pile research
-20-
-------
loop was constructed and installed in the Brookhaven
Graphite Reactor and was tested with pile neutron and
gamma background radiation. The loop is essentially
a highly versatile pilot plant.
(24)
The chemonuclear loop basically consists of
a doubly contained, recirculating gas system which has
been inserted into the lower section of the core of the
Brookhaven Graphite Research Reactor. All control
functions are maintained in extended out-of-pile sec-
tions. The loop is designed to utilize either pile
radiation (reactor neutron and gamma energy), or the
fission fragment energy of uranium containing alloy
foils' '' which are especially fabricated to effic-
iently impart this energy into the radiation system.
A flowsheet of the chemonuclear loop is shown in
Figure 2. Preliminary tests have been made of ozone
yields from oxygen, using only pile neutron and gamma
radiation.(27) jn general, the results show that lower
temperatures increase radiation yields and concentra-
tions of ozone, as do higher pressures. It has also
been found that the addition of nitrogen has a strong
enhancing effect on the yield, depending on the system
pressure and nitrogen concentration. Figure 3 shows a
time history of a typical run in which an ozone concen-
tration of 500 ppm was obtained despite the relatively
low dose rate (2.4 megarads/hr) available from pile
radiation. The integral G-value (radiation yield) for
the 15.6% N2 concentration was calculated to be in the
order of 8 molecules/100 eV. Subsequent -work has re-
sulted in initial G-values as high as 12.
A summary of the radiation chemistry and chemonuclear
loop results indicates the following:
1. G-value yields for ozone formation from oxygen
can be obtained ranging from at least 10 to as high as
15.
2. There appears to be no effect of the type of
radiation on the yield (no LET effect). Thus gamma
radiation from sources such as Co and Cs-^V or beta
radiation from Sr ^ and electron accelerators or fission
fragments from direct fission of uranium should give
similar yields of ozone.
-21-
-------
FLOW METER-
VENT TO
HOLDUP AND STACK
SHIELDED CONTAINMENT
GAS TO WATER COOLER
GAS TO WATER COOLER
ANALYTICAL
CUBICLES
I
NJ
SILVER REACTOR
C.W.S. FILTER
LOW TEMPERATURE
SEPARATOR
MASS SPECTROMETER
PROCESS GAS
CHROMATOGRAPH
C.W.S. FILTERS
REFRIGERATED COOLER
- PROCESS
PHOTOMETER
COMPRESSOR
ACTIVITY PROBE
ELECTRICAL HEATER
LOOP CIRCULATOR
GAS SUPPLY
FUEL PACKAGE IN
RETRACTABLE CARRIAGE
SAMPLER
AND SCINTILLATION CRYSTAL
FLOW SHEET
BROOKHAVEN CHEMONUCLEAR IN-PILE RESEARCH LOOP
FIGURE 2
-------
T
T
PRESSURE =800 PSIG
TEMPERATURE = -30 °F
o
cvJCO
CO
I
E
Q.
Q.
I
2
O
z
o
o
UJ
z
o
N
O
500
400
300
HISTORY OF
RUN No.3
FEB. 11-14, 1969
50
60
70
80
TIME AFTER STARTUP - HOURS
FIGURE 3
-------
3. The steady state concentration of ozone is
almost a direct function of the intensity. Concentra-
tions as high as 0.5% have been obtained with fission
fragment energy.
4. After conditioning the surface, ozone can be
produced continuously in a steel processing system.
5. The yield and concentration of ozone tends to
increase with pressure; tests up to 60 atm have been
made.
6. The yield of ozone is favored by lower temper-
/ 9p\
atures due to the thermal instability of ozone. \*°>
High yields have been obtained between -20 and 0°C.
7. Additions of nitrogen in the order of a few
per cent by volume has a marked enhancing effect on the
yield.
5.4 New Methods
In addition to isotopic and chemonuclear ozone
development work, Brookhaven National Laboratory is
also seeking to improve the electric discharge process.
A promising method which combines both radiation and
electric discharge is described in Appendix A. Lower
energy requirements and higher yields are expected with
this system.
-24-
-------
5.5 PROCESS DESCRIPTIONS
5.5.1 Isotopic Process
Figure 4 is a flowsheet of an isotopic source ozone
generator. Ozone generated as 1% by volume in an 02-N2
stream is sent to the Acid Mine Drainage (AMD) treatment
plant for use in the ozone contactors, and the oxygen is
recycled back to the ozone generator for re-use. The
30°F temperature maintained by a refrigerated cooler
results in higher ozone yields per unit of input energy-
5.5.2 Electric Discharge Process
A similar flowsheet for the electric discharge ozon-
izer system is shown in Figure 5. Although an air separ-
ation plant is included, this would apply only to larger
systems such as a 6 x 10 gal. per day AMD plant with
high Fe++ contents, where ozone production in the order
of 10 tons per day is required. Normally, oxygen gas
from cylinders is employed, as in the isotopic source
case. Ozone can also be produced by electric discharge
through an air stream, thus eliminating oxygen recycle
equipment. Since this requires higher energy input than
with pure oxygen, the savings in recycling equipment may
be offset by higher investment in ozonizers. The econ-
omics of both air and oxygen feed are discussed in a
later section of the report.
5.5.3 Chemonuclear Process
The third method of ozone production evaluated is
the chemonuclear reactor, which employs the energy of
nuclear fission to impart energy into reactant streams
in the same manner as do gamma rays from isotopes. since
a nuclear reactor is employed as the energy source, the
process is applicable to large-scale production. Thus,
the method can be considered from a central production
plant aspect only.
The chemonuclear method is illustrated in Figure 6.
An oxygen-nitrogen stream from an air-separation plant
is passed through.a critical array of specially designed
fuel elements.' The fuel consists of uranium-aluminum
alloy assemblies coated on an aluminum plate substrate.
-25-
-------
(Ji
I
1
02 STORAGE
N2 STORAGE
30° F.
COOLER
ISOTOPIC
OZONE
GENERATOR
—-IXH
DRYERS
02 RETURN COMPR
FROM AMD PLANT
-»- 03/02TO AMD TREATMENT PLANT
OZONE GENERATION USING ISOTOPIC SOURCES
FIGURE 4
-------
MAKE-UP 02
AIR
SEPARATION
PLANT
N2,Ar,C02
.AIR
I
NJ
-*»H20,C02
COOLERS
RECYCLED 02
COMPRESSOR
DRYERS
OZONATOR
02 TO WATER PLANT
POLLUTED
WATER
WATER
TREATMENT
PLANT
TREATED
WATER
ELECTRICAL DISCHARGE OZONE PROCESS
FOR WATER TREATMENT
FIGURE 5
-------
AIR
I
fo
00
I
-IOC
-7C
OZONE
CHEMO-
NUCLEAR
REACTOR
0,
Kr
Xe
NVFP
AIR COj,N2)Ar
N,
AIR
SEPARATION
PLANT
F-ll
-IIC
OZONE
ABSORBER
-10 °C
55 ATM
_ 1
-3(
20 C
-II
LER
IB'
)C
AAA>
>A/V\
A/--
Kr TO WASTE
COND. C-
-80 C C_
Kr
DIST.
5.7 ATM
52 °C
REBOILER
nnnn
^__ (
REFRIG.
N
•»•
-63C
~-60C
!
_ n
- U3
w
Xe TO WAS
Os , N2 f
CONO. C~
-63 C C_
OZONE
DIST.
17 ATM
120 °C
REBOILER
(TfW)
s™» 3K£
Xe
OIST.
F_H Xe 16 ATM
NVFP
0, IN AIR TO
WATER TREATMENT
REFRIG.
F-ll
NVFP
F-ll
PURIF.
1
STEAM
40 C
STEAM
Oj.Xe.F-ILNVFP
ISC" F-ll
52 C
62C
-AAA/W-
100 C
HOC
Kr, Xe,0,
NVFP
NVFP
TO
WASTE
STORAGE
F-l
CHEMONUCLEAR OZONE GENERATION AND PURIFICATION FOR WATER TREATMENT
FIGURE 6
-------
The alloy coating is only 0.25 mil thick, and would
release at least 20% of the fission fragment energy into
the reactant gas, which is maintained at a 30°F average
temperature.
A major potential problem in the process is the
removal of fission products from the ozone-containing
gas stream, particularly the volatile noble gases
krypton and xenon. The non-volatile solid fission
products are physically removed by deposition on sur-
faces and by filtration. The volatile gases may be
removed by a Freon absorption-stripping system,(29) as
shown in Figure 6. This is a multi-column separation
scheme which depends upon the solubility of krypton and
xenon in Freon at low temperatures, which are fairly
high. This type of system has been shown to be feasible
for nuclear fuel reprocessing plants.' ''
-29-
-------
6. ECONOMIC ANALYSIS
6.1 ON-SITE PLANTS
6.1.1 Isotopic Process
Because of its limited capacity the Isotopic Pro-
cess lends itself mainly for applications to on-site
treatment plants.
1 The isotopes chosen for evaluation were Co and
Cs . Co is presently used widely in radiation pro-
cessing. 137Cs is under development as a radiation
source, and could become available at low cost since it
is a by-product of the nuclear power industry. For this
study, the source types produced at BNL, described in
Table 5, were used as reference sources. The generator
concept is that of a vessel, as shown in the sketch in
Figure 8, with the sources arrayed in a circular pattern
inside the vessel. The optimum arrangement to provide
minimum energy loss, both to the vessel walls and to
other sources, is that the source array have a diameter
one- third that of the vessel. The amount of energy de-
posited in the reactant stream flowing through the vessel
is a function of the pressure, since higher pressures
result in a denser medium which captures more energy,
thus is more efficient from an energy standpoint. This
is counterbalanced by the greater cost of high-pressure
vessels, compression equipment, and power requirements.
The analysis is then one of optimization. Figure 7 shows
the energy deposition from 60Co and 137Cs at various
pressures through different thicknesses of oxygen layers,
and is a guide for selecting pressure vessel diameter.
Isotope requirements can be calculated from the
equations:
6850T _ 6()
C = -- f°r C°
= 26^00T 137
GEM
-31-
-------
TABLE 5
CHARACTERISTICS OF BNL GAMMA SOURCES
^ ~
Co Cs
Power, Curies 5-, 000 4,000
Size, in. 13-1/16 x 0.70 x 1/8 13% x 1-1/8 x 3/8
Half-life, yrs . 5.3 30
Gamma Energy, MeV 2.5 0.66
2
Cross-Section, cm /g 0.055 0.078
Heat Generation, w/KCi 14.8 5.0
-32-
-------
ur
I
10 20 30 40 50
OXYGEN LAYER THICKNESS - INCHES
60
GAMMA-RAY ENERGY ABSORPTION IN 02 VS
PATH LENGTH AT HIGH PRESSURE
FIGURE 7
-------
10
ALL VESSELS 20 FEET HIGH
o
\
in
I
O
_l
UJ
O
N
O
10
10 ft dia
8 ft dia
6ft dia
4 ft dia
^r— 10 ft dia
- 8ft dia
6 ft dia
2 ft dia
4ft dia
6tbo -
137Cs
SOURCE
ARRAY
10
2ft dia
CIRCULAR SOURCE CONFIGURATION
OF DIAMETER= 1/3 VESSEL DIA.
VESSEL
YIELDS INCLUDE:
90% SOURCE EFF.
90% GEOMETRIC EFF.
1000 1500 2000
OXYGEN PRESSURE-psi
OZONE YIELD vs OXYGEN
PRESS. FOR VESSELS OF VARYING DIAMETERS.
FIGURE 8
-34-
-------
C = Amount of isotope required, megacuries
T = Ozone production quantity, tons/day
G = G value for energy absorbtion, molecules/100 eV
E = Energy deposition efficiency in gas, a fraction
M = Molecular weight of product (0 = 48)
The capacity of ozone obtainable for different ves-
sel diameters and pressures is shown in Figure 8. Costs
of pressure vessels, compressors and isotopes were esti-
mated for the various sizes and pressures, and it was
found that for the cases where large ozone quantities
are required, 10 ft dia. vessels are optimum, and multiple
vessels were generally required to meed the demands of
most cases. In addition to the above-mentioned costs,
costs of shielding for radiation protection, installation,
and isotope investment and replacement were factored in.
For ^OGO, costs of 10, 20, and 30£ per Ci were chosen.
Present day costs are about 300 per Ci for large quanti-
ties, and it was assumed that as usage increased, cost
1 "3 7
would decrease. -LJ/Cs was assumed to cost 1, 5, 10 and
15£ per Ci. These low costs may not be unreasonable,
1 ^ "7
since -"--^'Cs may become readily available in the near
term from nuclear power fuel reprocessing plants at low
cost due to the problem of long-term disposal of the
isotopes from spent fuel elements. It is conceivable
that 137cs may be obtained by mere payment of the ship-
ping costs.
Figure 9 shows the depreciation of the investment
costs (at 7.3% depreciation rate) expressed in dollars/
Ib. ozone for the isotopes, Figures 10 and 11 show the
production costs of ozone by this method, and Figure 12
expresses the lowest ozone production costs from iso-
topes in dollars per 1000 gal. This production cost
includes depreciation, operating costs, and oxygen cost.
Note that this is the cost of ozone production only, and
does not include the AMD treatment plant.
The ozone cost for water treatment is obtained from
the equation:
LP
T =
W
-35-
-------
I
to
3.00
2.80
2.60
£ 2.40
« 2.20
g 2.00
Jf 1.80
| 1.60
ft '-40
2 1.20
UJ
o L0°
o .80
.60
.40
.20
i r
T
T
10
7.3% FIXED CHARGE RATE
OPTIMIZED PRESSURE
ISOTOPE COSTS IN * PER CURIE
60CO
137
CS
151, 2000 psi
.0«,2000p.i 300,2000,,.,
JOC,2000p»l
I0_<,2000 psi ~
i i i i i i i
10 10
OZONE PRODUCTION, Ibs/DAY
INVESTMENT COSTS FOR OZONE
USING ISOTOPIC RADIATION
10
10
FIGURE 9
-------
I
OJ
-J
I
CD
0:2.80
LU
Q_
£2.40
§2.00
i
to
8 '-60
e 1.20
.80
o
o
ID
Q
O
or
Q_
LU
o
N
O
.40
~~\ \ I I I I 111 I I I I I I 111 I I I I I I I 11 I I I I I I 11
154/Ci
lOt/Ci
5
-------
I
U)
00
I
10
100 1000 10,000
DAILY OZONE PRODUCTION-LBS
100,000
COBALT-60 OZONE GENERATOR, 2000 psi PRESSURE
PRODUCTION COST vs CAPACITY FOR VARYING SOURCE COSTS
FIGURE 11
-------
3.50
OJ
kO
I
0.25 MM
GAL/DAY
100 200 300 400 500 600 700 800 900 1000
Fe"1"* CONTENT-ppm
ISOTOPIC SOURCE OZONIZERS.COST OF AMD
OZONATION AT VARYING DAILY STREAM FLOWS
AND Fe* CONTENTS-OXYGEN FEED AND RECYCLE
FIGURE 1 2
-------
where:
T = ozone cost, C/1000 gal.
P = ozone cost, £/lb.
L = ozone required, Ibs/day
W = AMD flow, thousand of gal./day
All production costs in this study were based on
an annual fixed charge rate of 7.3%, which is commonly
used by utility-type industries.
It is readily apparent that this method is a rela-
tively high cost system; despite the high efficiency,
the large investment necessary (mainly in isotopic
sources) and the high replacement cost for isotopic
decay offers little inducement for development of this
method for large-scale use in this particular applica-
tion, except possibly for very low Fe AMD streams.
For example, the investment cost for ozone production
for a 250,000 gpd AMD plant at a Fe+2 concentration of
300 ppm is $664,000 using 60co at 10* per Ci, or
$479,000 using 137Cs at 1£ per Ci. Later in this
report, it will be seen that the came capacity can be
handled by electric discharge units for an investment
cost of $60,000.
The isotopic process may become interesting for
treatment of acid mine drainage for Fe+2 contents below
50 ppm. The only advantage of an isotope source is that
no primary power supply is required. l37Cs isotope has
a half life of 30 years, and thus plant life is long.
However, auxiliary power from pumps and compressors would
be required.
-40-
-------
6.1.2 Electric Discharge Process
For on-site AMD treatment plants, with ozone pro-
duced at the site, the electric discharge method is a
feasible process. The largest usage at one site con-
sidered in this study requires 12.5 tons per day ozone
to treat 6 million gal. AMD containing 1000 ppm Fe++,
and the smallest, for treatment of 250,000 gal. per
day with a Fe++ content of 50 ppm, requires only 52 Ib
per day ozone. Both once-through air feed and recycled
oxygen feed were considered in the evaluation. Invest-
ment and production costs for both methods are listed
in Table 6 through 9, and the data is plotted in Fig-
ures 13, 14 and 15 in terms of ozone cost per Ib and
per 1000 gal. AMD. Note once again that these are
only the costs of ozone production, and do not include
the AMD treatment plant itself. These are evaluated
later in the report. Costs of ozonizers and auxiliary
equipment were obtained from a commercial ozone equip-
ment manufacturer.(32) cost of purchased oxygen was
obtained from Linde Co.'33) Purchased oxygen was
assumed in all oxygen cases except the 25,000 Ib per
day ozone plant, where the cost is based on an on-site
oxygen plant, since the saving to be gained is very
significant. The cost of purchased oxygen is given
in Table 10. .The oxygen plant results in a saving of
about 1£ per Ib ozone, which reduces annual operating
costs by $75,000.
Once-through air feed ozonizers are more economi-
cal at capacities up to about 200 Ib per day. This
occurs because the higher investment cost for ozonizers
is overridden by the high purchase cost of oxygen at
low capacities. Above 200 Ib per day ozone requirement
the recycled oxygen system is the choice.
-41-
-------
TABLE 6
OZONE INVESTMENT COSTS
ON-SITE GENERATION, ONCE-THROUGH AIR FEED
Cost in Thousands of Dollars
Lb/Day Ozone
Energy Req't. Kw-Hr/lb.
Ozonizers
Auxiliaries
Construction
Total Investment
50
7.25
7.5
3.9
3.5
14.9
9.75
7.5
5.2
4.7
17.4
1000
7.25
118
48
44
210
9.75
140
65
59
264
7500
7.25
620
159
135
914
9.75
780
214
180
1,174
25,
7.25
1,720
410
400
2,530
,000
9.75
2,240
550
530
3,320
TABLE 7
OZONE PRODUCTION COSTS
OH-SITE GENERATION, ONCE-THROUGH AIR FEED
Costs in £/lb
Lb/Day Ozone 50 1,000 7,500 25,000
Energy Req't, Kw-Hr/lb. 7.25 9.75 7.25 9.75 7.25 9.75 7.25 9.75
Depreciation 7.27 8.50 5.12 6.44 2.97 3.82 2.47 3.24
Labor 1.80 1.80 1.80 1.80 1.80 1.80 1.80 1.80
Maintenance 1.80 1.80 1.80 1.80 1.80 1.80 1.80 1.80
Power* 6.20 8.20 6.20 8.20 6.20 8.20 6.20 8.20
Total 17.07 20.30 14.92 18.24 12.77 15.62 12.27 15.04
*Includes additional 0.5 KW-Hr/lb for auxiliaries.
-42-
-------
TABLE 8
OZONE INVESTMENT COSTS
ON-SITE GENERATION, RECYCLED OXYGEN FEED
Cost in Thousands of Dollars
Lb/Day Ozone
Energy Req't, KW-Hr/lb.
Ozonizers
Auxiliaries
Construction
Total
Oxygen Plant
Total with Oxygen Plant
50
1000
7500
3.75 5.00 3.75 5.00 3.75 5.00
3.75 5.00 65.0 86.5 353 470
4.00 5.35 50.0 66.5 165 220
2.00 2.67 25.0 33.3 90 120
9.75 13.02 140.0 186.3
608 810
TABLE 9
OZONE PRODUCTION COSTS
ON-SITE GENERATION, RECYCLED OXYGEN FEED
Cost in £/lb
Lb/Day Ozone
Energy Req't, KW-Hr/lb.
Depreciation
Labor
Maintenance
Oxygen
Power*
25,000
3.75 5.00
950 1265
425 565
225 300
1600 2130
350 350
1950 2480
50
3.75
4.75
1.20
1.20
12.60
5
6
1
1
12
.00
.36
.20
.20
.60
3
3
1
1
4
1000
.75
.42
.20
.20
.00
5.00
4.55
1.20
1.20
4.00
3
1
1
1
2
7500
.75
.98
.20
.20
.00
5.00
2.64
1.20
1.20
2.00
3
1
1
1
0
25,
.75
.56
.20
.20
.60
000
5.00
2.08
1.20
1.20
0.60
3.83 4.82 3.83 4.82 3.83 4,82 4.00 5.00
23.58 26.18 13.65 15.77 10.21 11.86 8.56 10.08
*lncludes additional 1.04 KW-Hr/lb for auxiliaries, and 1,25 KW-Hr/lb for
25,000 Lb/Day plant case where oxygen plant is used.
-43-
-------
TABLE 10
*
COST OF PURCHASED OXYGEN GAS
Monthly Usage
3** 3**
1st 20,000 ft $1.05/100 ft
Next 60,000 .50 "
Next 120,000 .33 "
Next 800,000 .17 "
Over 1,000,000 .13 "
*
From Linde Co., Div. Union Carbide Corp.
** 3 o
Ft expressed at 70 F, 1 ATM.
-44-
-------
(JT
I
CD
•e-
i
O
O
2
O
h-
o
Q
O
cr
Q_
LU
O
M
O
£
O
30
25
20
15
10
0
I I I I I I 111 I I I I I I I 11
5.0 KW HR/LB
n i i i i 1111 i I I i i 111
OXYGEN FEED WITH RECYCLE
AIR FEED
3.75 KW HR/LB
10
9.75 KW HR/LB
7.25 KW HR/LB
i i
i i i
I
i 11
i i i i
100 1,000 10,000
DAILY OZONE PRODUCTION - LBS
100,000
ELECTRIC-DISCHARGE OZONIZERS,PRODUCTION
COST vs CAPACITY AT VARIOUS POWER
CONSUMPTIONS, AND FOR OXYGEN AND AIR FEEDS
FIGURE 13
-------
70
o
o
o
cr
Ld
CL
(/)
50
40
z
Ld
O
h-30
(f)
O
o
o
I
o
20
10
0.25MM-
0.50MM-
.0 MM-
6.0 MM-
GAL/DAY
7.25KWHR/LB03
9.75KWHR/LB03
0 100 200 300 400 500 600 700 800 900 1000
Fe++CONTENT-ppm
ELECTRIC DISCHARGE OZONIZERS.COST OF AMD
OZONATION AT VARYING DAILY STREAM FLOWS
AND Fe++CONTENTS-ONCE THROUGH AIR FEED
FIGURE 14
-------
70
o
o
o
50
LU
CL
£40
LJ
O
J_30
o
o
20
o
g
o
N
O
10
0.25 MM
0.50 MM
1.0 MM
6.0 MM
0.25 MM
0.50 MM
1.0 MM
6.0 MM
3.75 KW HR / LB 03
5.0 KW HR / LB 03
0 100 200 300 400 500 600 700 800 900 1000
Fe++ CONTENT- ppm
ELECTRIC DISCHARGE OZONIZERS.COST OF AMD
OZONATION AT VARYING DAILY STREAM FLOWS
AND Fe++CONTENTS-OXYGEN FEED AND RECYCLE
FIGURE 15
-------
6.2 CENTRAL OZONE PRODUCTION PLANTS
6.2.1 Ozone Shipping and Storage
Economies can be achieved for most chemicals by
large-scale central facilities, and ozone is no excep-
tion. However, the problem of storage and shipment to
usage points has generally discouraged efforts to gen-
erate ozone except at the point of use. In the last
few years, some producers of industrial gases have
started to ship ozone, dissolved in Freon solvents, on
a small scale. When ozone is dissolved in Freon at
moderately low temperatures, the storage life and stab-
ility of the compound are greatly enhanced. By this
method, ozone can be shipped in interstate commerce.
Enlarging upon existing technology, a method for large-
scale ozone shipment was devised, as shown in Figure 16.
The ozone-air mixture from the central ozone plant is
stripped of air in a Freon-11 absorber at -60°C. The
ozone, now dissolved in Freon-11, is kept in a holding
tank for distribution in insulated tank trucks, similar
to those used for distribution of liquified natural gas
and nitrogen. The truck delivers the ozone to the AMD
site, where the ozone-Freon mixture is transferred to
an insulated storage tank. As the ozone is required
for AMD treatment, it is withdrawn through a warming
coil, in which ozone and some Freon is flashed. In a
partial condenser, the flashed Freon is recondensed,
and the ozone gas is mixed with air and passes to the
AMD contactors. Condensed F-ll is returned to the
central ozone plant in the now empty tank truck.
Figure 17 illustrates how ideally the central plant
distribution system fits the Pennsylvania AMD situation.
The map shows where the coal-mine drainage counties are
located, and also shows the number of draining mines(34'
in each county. The geography is such that the shipping
distance ranges from a radius of 60-75 miles maximum
from a central plant located in Indiana County. This
would also offer the possibility of obtaining mine-mouth
power from the Keystone generating station. In this case,
favorable off-peak power rates for the continuously
operating ozone plant might be obtained.
-49-
-------
F-ll COOLER
o
I
AIR-
), -AIR
'ROM 0, PLANT
r
FROM TRUCK
n *
x~J-^ — -
ABSORBER
2 ATM
-60°C
"" _^*">
^
AJR __
°3 IN
F-ll
HOLDER
L^
-60C F-ll FROM RETURNED TRUCK
,.J^T*T^r\ ,^^^__
1 mf AIR^^j
03 IN F-ll - -B-£'-^--
0, IN F-ll , ,
3
LJAl PM M P D— .
nULUINb /**• -\
TANK k ( INSULATED A
V f <
LTV— X-TV-S— J
Pn • 1
-a*-1
CENTRAL PLANT 03 FACILITY
^_ J
AIR
i 03 -AIR TO
03 AMD TREATMENT
^^ ^ H f^ ^1
WARMING \ +. F-ll TO
COIL cnr"~"* F~' RETURNING
C60CJ F- 1 HOLDING TRUCK
\ . ^toi TA kll/ WV/r\
F-ll TANK
CONDENSER 1
AMD TREATMENT SITE FACILITY
OZONE STORAGE AND DISTRIBUTION SYSTEM
FIGURE 16
-------
I
Ul
NUMBER IN PARENTHESIS IS NO. OF DRAINING MINES
(DATA FROM PENNA.DEP'T OF HEALTH)
COUNTY KEY
I. ALLEGHENY
2. ARMSTRONG
3. BEAVER
4. BEDFORD
5. BUTLER
6. CAMBRIA
7. CENTRE
8. CLARION
9. CLEARFIELD
10. FAYETTE
I I. GREENE
12. INDIANA
13. JEFFERSON
14. LAWRENCE
15. SOMERSET
16. WASHINGTON
17. WESTMORELAND
DISTRIBUTION OF DRAINING COAL MINES IN PENNSYLVANIA COUNTIES
FIGURE 17
-------
(34)
Data from the Pennsylvania Department of Health
show 2,158 known draining coal mines in the state.
Their total flow is 486 x 105 gallons per day, or an
average flow of approximately 250,000 gal. per day.
Their average Fe++ content is about 200 ppm. To treat
the total quantity requires an ozone plant with approx-
imately 200 tons per day capacity.
6.2.2 chemonuclear Process and Comparison with Electric
Discharge Process
Cost estimates were made of central ozone generat-
ing plants ranging from 40 to 400 tons per day- Elec-
tric discharge and chemonuclear methods were compared,
and the ozone costs are shown in Figure 18. In terms
of ozone cost for water treatment, the results are shown
in Figure 19 at various plant capacities. Two power
costs are shown for the electric discharge case; because
of the large power requirement, this variable strongly
affects electric discharge economics. Figure 19 also
assumes a 5.0 kw-hr/lb. power consumption. For the
chemonuclear cases. Figure 19 shows the least efficient
(i.e., most conservative) combinations of G-value and
energy deposition efficiency. Investment and operating
costs for these cases are itemized in Table 1 through
14 and energy requirements in Tables 15 through 18.
The definite advantage of chemonuclear over elec-
tric discharge is readily apparent from Figure 19. For
example, taking the 200 ton/day ozone case, which would
serve all of Pennsylvania's AMD treatment requirements
(486 x 10 gal/day), and the average Fe content of
200 ppm, the most conservative electric discharge ozone
cost (6 mil power) is 5C/lb ozone. For the same case,
the most conservative chemonuclear cost (G=10,E=20) is
3£/lb, thus resulting in a 40% saying in ozone produc-
tion cost.
The basis for the estimates are as follows:
Chemonuclear Case - Fission Fragment Reactor
1. 20% of the reactor heat is removed by recycle
gas refrigeration, and the remainder by cool-
ing water.
-52-
-------
GO
I
6.0
5.0
CO
8 4.0
o
o
cr
o_
o
M
O
3.0
2.0
1.0
KWH/LB MILS/KWH
— 5.0 6
5.0 5
3.75 6
3.75 5
G = IO, E = 0.20
G=I5, E= 0.20
G=IO, E= 0.35
G=I5,E= 0.35
— ELECTRIC DISCHARGE
- CHEMONUCLEAR
G= G VALUE, MOLECULES/IOOeV
FOR 03
E= FISSION FRAGMENT ENERGY
DEPOSITION EFFICIENCY
0
0
100 200 300 400 500
OZONE PLANT CAPACITY-TONS/DAY
600
PRODUCTION COST OF OZONE.
CONVENTIONAL vs CHEMONUCLEAR PROCESSES
FIGURE 18
-53-
-------
30
o
o
o
\
o
I
co
o
o
z
o
z
o
N
O
25
20
I 0 -
5 -
—I 1 1 1—
ELECTRIC DISCHARGE
CHEMONUCLEAR
6 MIL POWER
5 MIL POWER
G=IO, « = 0.20
G = I5,« = 0.20
200 TON/DAY 03 CAPACITY -
Fe"1"1" CONTENT-ppm
j_
j_
_L
_L
o
o
o
\
o
I
I-
co
o
o
z
g
z
o
N
O
30
25
20
I 5
ELECTRIC DISCHARGE
CHEMONUCLEAR
6 MIL POWER
5 MIL POWER
G = IO,€=0.20
400 TON/DAY 03 CAPACITY
Fe++CONTENT- ppm
I I II I
200
400
600
800
1000
200
400
600
800
1000
30
o
o
o
\
o
l
I-
co
O
o
z
o
N
O
25 -
20 -
I I I I
ELECTRIC DISCHARGE
CHEMONUCLEAR
6 MIL POWER
5 MIL POWER
G =10,, = 0.20
G = I5,« = 0.20
40 TON/DAY 03 CAPACITY
Fe+ + CONTENT-ppm
30
200
400
600
800
1000
o
o
o
o
o
I
CO
o
o
O
N
O
I I I I
ELECTRIC DISCHARGE
CHEMONUCLEAR
6 MIL POWER
5 MIL POWER
,« = 0.20
= I5,«=0.20
100 TON/DAY 03 CAPACITY
Fe++CONTENT-ppm
I 5-
I 0-
200
400
600
800
1000
ELECTRIC DISCHARGE VS. CHEMONUCLEAR AMD TREATMENT COSTS USING
OZONE FROM LARGE CENTRAL PLANTS (OZONE PRODUCTION COST ONLY)
FIGURE 19
-------
TABLE 11
CHEMONUCLEAR OZONE
TOTAL PRODUCTION COST -
T Capacity Ton 03/Day
G Values, Molecules/100 eV
E - Energy Deposition Efficiency
P Power Level of Reactor, MW(t)
Depreciation @ 7.3%
Nuclear Fuel Cycle
Labor
Maintenance
Power
Total £/lb. 03
T Capacity, Tons /Day
G - Values, Molecules/100 eV
E Energy Deposition Efficiency
P Reactor Power, MW(t)
Depreciation @ 7.3%
Nuclear Fuel
Labor
Maintenance
Power
Total, C/lb. 03
T Capacity Ton 03/Day
G Values, Molecules/100 eV
E Energy Deposition Efficiency
P Power Level of Reactor, MW(t)
Depreciation @ 7.3%
Nuclear Fuel
Labor
Maintenance
Power
Total - c/lb. 03
T Capacity, Tons/Day
G - Values, Molecules/100 ev
E - Energy Deposition Efficiency
P Reactor Power, MW(t)
Depreciation @ 7.3%
Nuclear Fuel
Labor
Maintenance
Power
Total c/lb . 0-,
0
42
2
1
0
0
1
5
0
106
1
1
0
0
1
4
0
212
1
1
0
0
1
4
.20
.5
.36
.30
.50
.16
.14
.46
.20
.84
.30
.25
.12
.14
.65
.20
.42
.30
.16
.10
.14
.12
40
10
0
24
2
0
0
0
0
4
100
10
0
60
1
0
0
0
0
3
200
10
0
121
1
0
0
0
0
3
-------
TABLE 12
T - Capacity, Tons 03/Day
G - Values, Molecules/100 eV
E - Energy Deposition Ef
P - Reactor Power, MW(t)
07 Plant
Refrigeration Equipment
Nuclear Reactor
Freon Plant
Compressors
Total
T
G
E
P -
Capacity, Tons 03/Day
Values, Molecules/100 eV
Reactor Power, MW(t)
02 Plant
Refrigeration Equipment
Nuclear Reactor
Freon Plant
Compressors
Total
T - Capacity, Tons
G Values, Molecules/100 eV
E Energy Deposition E
P - Reactor Power, MW(t)
Oxygen Plant
Refrigeration
Nuclear Reactor
Freon Plant
Compressors
Total
T - Capacity, Tons 03/Day
G - Values, Molecules/100 eV
E - Energy Deposition Efficiency
P - Reactor Power, MW(t)
Oxygen Plant
Refrigeration
Reactor
Freon Plant
Compressors
CHEMONUCI£AR 020NE
INVESTMENT COST - MILLION DOLLARS
•y
iO eV
ificier
•y
>0 eV
ificier
:)
y
0 eV
ficier
y
0 eV
ficier
40
10
icy 0.20 0.35
42.5 24.2
1.00 1.00
0.43 0.25
4.25 4.25
2.00 2.00
0.23 0.13
7.91 7.63
100
10
icy 0.20 0.35
2.00 2.00
1.07 0.63
7.50 7.50
4.00 4.00
0.50 0.28
15.07 14.41
200
10
icy 0.20 0.35
212 121
2.90 2.90
2.14 1.26
11.60 11.60
5.80 5.80
0.90 0.50
23.34 22.06
400
10
icy 0.20 0.35
424 242
3.50 3.50
4.30 2.50
17.40 17.40
7.00 7.00
1.60 0.83
33.80 31.23
0.20
28.3
1.00
0.30
4.25
2.00
0.13
7.68
0.20
2.00
0.75
7.50
4.00
0.28
14.53
0.20
142
2.90
1.50
11.60
5.80
0.50
22.30
0.20
284
3.50
3.00
17.40
7.00
0.83
31.73
40
15
0.35
16.1
1.00
0.17
4.25
2.00
0.10
7.52
100
15
0.35
2.00
0.43
7.50
4.00
0.22
14.15
200
15
0.35
80
2.90
0.86
11.60
5.80
0.40
21.56
400
15
0.35
160
3.50
1.70
17.40
7.00
0.70
30.30
-56-
-------
TABLE 13
ELECTRIC DISCHARGE PRODUCTION COST - f/LB
Capacity - Tons /Day
Power - KWH/lb.
Depreciation @ 7.37»
Power CostX @ 5 Mil/KWH
@ 6 Mil/KWH
Labor
Maintenance
Total Cost @ 5 Mil/KWH
@ 6 Mil/KWH
40
3.75
1.72
2.50
3.00
0.25
0.05
4.52
5.02
*
Power Cost includes additional 1.25
ELECTRIC
5.00
2.19
3.12
3.75
0.25
0.05
5.61
6.24
KWH/Lb
TABLE
3
1
2
3
0
0
4
4
.75
.58
.50
.00
.13
.05
.26
.76
. for
14
DISCHARGE
100
5
2
3
3
0
0
5
5
.00
.03
.12
.75
.13
.05
.33
.96
OZONE
3.75
1.47
2.50
3.00
0.08
0.04
4.09
4.59
auxiliaries, as
200
5
1
3
3
0
0
5
5
400
.00
.90
.12
.75
.08
.04
.14
.77
shown in
3.75
1.36
2.50
3.00
0.04
0.04
3.94
4.44
Table 8
5.00
1.78
3.12
3.75
0.04
0.04
4.98
5.59
) .
OZONE
INVESTMENT COSTS - MILLION
Capacity Tons /Day
Power Requirements
Ozonizers
Recycle Equipment
Construction
Oxygen Plant
Total
40
3.75
2.62
1.36
0.64
1.00
5.62
5.00
3.49
1.81
0.85
1.00
7.15
3
5
3
1
2
12
.75
.97
.40
.60
.00
.97
DOLLARS
100
5
7
4
2
2
16
.00
.97
.53
.13
.00
.63
3.75
11.20
6.80
3.20
2.90
24.10
200
5
14
9
4
2
31
400
.00
.90
.05
.26
.90
.11
3.75
20.90
13.60
6.40
3.50
44.40
5.00
27.90
18.10
8.52
3.50
58.02
-57-
-------
TABLE 15
40 Tons/Day
02 Plant
Recycle Refrig.
Freon Plant
Compressors
100 Tons/Day
02 Plant
Refrig.
Freon Plant
Compressors
200 Tons/Day
02 Plant
Refrig.
Freon Plant
Compressors
400 Tons/Day
02 Plant
Refrig.
Freon Plant
Compressors
CHEMONUCLEAR OZONE SYSTEM
•OWER REQUIREMENTS - MW (e)
G=10
E=0.
0.
3.
0.
3.
7.
1.
7.
1.
8.
19.
3.
15.
2.
17.
38.
7.
30.
4.
35.
76.
20
7
0
4
5
6
75
50
0
75
00
5
0
0
5
00
0
0
0
0
0
0.
0.
1.
0.
2.
4.
10
1.
4.
1.
5.
12.
10
3.
8.
2.
10.
24.
10
7.
17.
4.
20.
48.
35
7
7
4
0
8
75
25
0
0
00
5
5
0
0
0
0
0
0
0
0
E=0.
0.
2.
0.
2.
5.
1.
5.
1.
5.
13.
3.
10.
2.
11.
27
7.
20.
4.
23.
54.
G=15
20
7
0
4
3
4
75
0
0
75
50
5
0
0
5
.0
0
0
0
0
0
0.
0.
1.
0.
1.
3.
15
1.
2.
1.
3.
8.
15
3.
5.
2.
6.
17.
15
7.
11.
4.
13.
35.
35
7
1
4
3
5
75
75
0
25
75
5
5
0
5
5
0
0
0
0
0
-58-
-------
TABLE 16
ELECTRIC DISCHARGE OZONE SYSTEM
POWER REQUIREMENTS - MW (e)
Ozonizers
@ 3.75 KWHR/lb,
Oxygen Plant
Auxiliaries
Total Power
40
12.5
0.7
3.5
16.7
Capacity - Tons/Day
100 200 400
31.3
1.8
8.7
41.8
62.5
3.5
17.5
83.5
125.0
7.0
35.0
167.0
Ozonizers
@ 5.00 KWHR/lb,
Oxygen Plant
Auxiliaries
Total Power
16.7
0.7
3.5
20.9
41.7
1.8
8.7
52.2
83.5
3.5
17.5
104.5
167.0
7.0
35.0
209.0
TABLE 17
CHEMONUCLEAR OZONE
ENERGY REQUIREMENTS KWH/LB.
Reactor, Thermal
02 Plant, Electrical
Refrigeration, Electrical
Compressors, Electrical
Total Electrical
G=10, E=0.20
12.80
0.21
0.95
1.05
2.21
G=15, E=0.35
4.85
0.21
0.33
0.39
0.93
-59-
-------
TABLE 18
ELECTRIC DISCHARGE OZONE
ENERGY REQUIREMENTS - KWH (ELECTRICAL)/LB. O.
Electric Ozonizers 3.75 5.00
0 Plant 0.21 0.21
Auxiliaries 1.04 1.04
Total Electrical 5.00 6.25
-60-
-------
2. Power cost--5 mils per kw-hr.
3. Gas refrigeration cost is $200 per ton.
4. 7.3% annual fixed charge rate on capital
investment. This is mainly taken from
the point of view of municipal water
treatment plants.
5. Labor costs
a. For the 200 and 400 ton/day plants, labor
is 6 men- per shift., 3 shifts, at $10,000
per man year.
b. For the 40 and 100 ton/day plants, 5 men
per shift, 3 shifts, at $10,000 per man
year.
6. Maintenance cost equals labor cost for the
400 ton/day plant, and is scaled for the
smaller plants by a 0.7 power factor of the
plant capacity.
7. Compressor and refrigeration costs were
obtained from commercial vendors, as were
oxygen plant costs.
8. Reactor costs obtained from estimate by Burns
& Roe and BNL based on G.E. and Westinghouse
price books.
9. The Freon system was estimated at twice the
cost of the oxygen plant because of additional
columns and shielding.
Chemonuclear reactor power is derived from the
equation:
101.5T
P GEM
where
P is the reactor power, megawatts
-61-
-------
T = ozone production, ton/day
G = G-value for ozone formation, molecules/100 eV
E = Energy absorption efficiency, a fraction
M = Molecular weight of product
Conventional Case - Electric Discharge Ozonizers
1. Costs of ozonizers obtained from Welsbach Bul-
letin 201;(32) also construction and recycle
equipment costs; the larger capacity costs
have been extrapolated using a 0.9 power
factor.
2. 7.3% fixed charge rate on capital.
3. Labor cost is half that of chemonuclear case.
4. Maintenance cost is equal to labor cost for
400 ton/day plant, and scaled by 0.9 power
factor for smaller plants.
The costs of the storage and distribution system
were evaluated. These include Freon-11 absorber, truck
fleet, storage tanks and refrigeration systems. A
breakdown for a typical case of a 250,000 gal/day AMD
plant with 200 ppm Fe+2, and based on a 200 ton per day
central plant, is shown in Table 19. The effect of
varying ferrous iron content is shown below:
+2
Fe Content-ppm. 50 300 10QQ
Ozone Distribution Cost-C/lb O3 4.3 4.3 3.30
Ozone Distribution Cost-C/1000 g/AMD 0.9 5.4 14.0
Maximum shipping distance is 75 miles; however, the
costs are insensitive to the shipping distance within
the Pennsylvania area.
Costs would not change much for larger AMD plants,
although some savings could undoubtedly be achieved
through optimization of the storage tank sizes and
delivery schedules.
-62-
-------
TABLE 19
STORAGE AND DISTRIBUTION COSTS
1. ADDITIONS REQUIRED TO 200 TON/DAY CENTRAL OZONE PLANT
Absorbers $1,225,000
Storage Tank & Pumps 625,000
Refrigeration Unit 1,225,000
Total 3,075,000
$3,075,000 @ 7.3% Fixed Charge Rate = O.lSC/lb 0
2. ADDITIONS TO 250,000 GAL./DAY AMD PLANT (208 Ib/day O )
Refrigeration Unit $ 4,000
O in F-ll Storage Tank 16,000
F-ll Return Tank 4,000
Total 24,000
$24,000 @ 7.3% Fixed Charge Rate = 3.0*/lb 0
3. FREON-11 INVESTMENT
3,350,000 Ib d> 20C/lb = $670,000 = 0.04<=/lb QS
Losses = .0036 Ib F-ll/lb C>3 = 0.07£/lb O3
4. TRAILER FLEET
85 Tandem Axle Twin Screw Tractors, each with 5300 Gal.
Vacuum Insulated Cryogenic Tank, d> $45,000 each = $3,825,000
(Includes 5 Spare Trucks) at 10 yr life, $382,000/yr
Labor - 80 Drivers, $10,000/yr = $800,000/yr
Total - $l,182,000/yr = l.OC/lb C>3
TOTAL SHIPPING AND DISTRIBUTION COST - 4.3C/lb O3
-63-
-------
Comparisons of one-site ozone production costs with
central plant generating and distribution costs show that
the central plants can offer savings of as much as 10-34C
per 1000 gal. AMD treated over the ranges of flow and
concentration considered in this study. The greatest
savings are at the high-flow, high Fe++ concentrations.
The chemonuclear method shows savings of l-7£ per 1000
gal. AMD over the electric discharge method in the range
of 40-200 tons/day ozone.
-64-
-------
6.3 AMD TREATMENT PLANT
The investment costs for the AMD treatment plants
at the mine sites are listed in Table 20. Operating
costs are listed in Table 21, and do not include the
cost of ozone. Labor is also excluded at this point
since it is assumed that for on-site ozone generation,
the operators from the ozone plant can perform the
minimal operations required in the treatment plant.
For the central plant cases, labor is not available
from the ozone plant for the minimal operations re-
quired at the AMD treatment site. Therefore, a labor
charge was added for these cases, amounting to 1 man-
hr at $5 per hr for the 250,000 gal/day case, or 2C
per 1000 gal. AMD. This charge is scaled down for the
larger AMD treatment plants. These situations are sum-
marized in Table 22-24, which give the total treatment
costs, including ozone, for both the on-site and central
ozone generating situations. These results are also
shown graphically on Figures 20 through 22. Total in-
vestment costs for on-site electric discharge ozonizers
and AMD treatment are shown in Table 25 and Figure 23.
Table 26 is a summation of the total treatment
costs for purposes of comparison. It shows that for
on-site ozone plants, recycled oxygen feed is prefer-
able to once-through air feed, with the exception of
the special case of low-flow, low Fe+2 streams. Cen-
tral ozone plants with distribution systems offer lower
costs than on-site plants, particularly for high Fe+2
and flow situations. Central chemonuclear plants re-
sult in lower costs than electric discharge facilities.
Treatment cost ranges, from Table 26, are seen to be
from 9-13C per 1000 gal. at 50 ppm Fe+2 over the flow
range of 250,000 to 6,000,000 gal. per day- For higher
Fe4^ concentrations, the treatment costs are 18-34C at
300 ppm, and 40-78* at 1000 ppm Fe+2 over the same AMD
flow range.
Central chemonuclear ozone plants with distribution
systems and high AMD flow rates offer the lowest costs
in the above ranges. The highest cost is for on-site
electric discharge ozone at low flow rates. An inter-
esting elaboration can be made here regarding central
-65-
-------
TABLE 20
AMD PLANT COST IN THOUSANDS OF DOLLARS
+2
AMD Flow Fe cone.
Case gal/day ppm
1 6 x 106
2
3
4 1 x 106
5
6
7 % x 106
8
9
1000
300
50
1000
300
50
1000
300
50
Oxidation
vessels
545
545
545
102
102
102
29
29
29
Agita-
tors
45
45
45
9
9
9
3
3
3
Lime-
stone
mill
39
20
9
16
6
4
4
4
4
Piping
&
neutr T
6
6
6
4
4
4
3
3
3
Misc., Hold-
Instr.& ing
control pond
6
6
6
3
3
3
1
1
1
24
24
24
4
4
4
1
1
1
Settl- Total
ing equipM&L) Total
pond indirects cost
48
48
24
8
5
4
3
3
2
713
694
659
146
136
130
44
44
43
855
830
790
175
163
156
53
53
52
e/iooc
gal.
3.6
3.4
3.2
4.3
4.0
3.8
5.2
5.2
5.1
-------
TABLE 21
AMD TREATMENT PLANT OPERATING COSTS* - £/1000 GAL.
AMD Flow 666
Gal./Day 0.25 X 10 1 X 10 6 X 10
Fe++, ppm. 50_ 300 1000 j>0 300 1000 J50 300 1000
Depreciation
(a> 7.3% 5.1 5.2 5.2 3.8 4.0 4.3 3.2 3.4 3.6
Power (§>
8 mil.Kw-Hr 3.2 3.3 3.5 3.2 3.3 3.5 3.2 3.3 3.5
Limestone
@ $5/Ton 0.5 1.6 4.4 0.5 1.6 4.4 0.5 1.6 4.4
TOTAL 8.8 10.1 13.1 7.5 8.9 12.2 6.9 8.3 11.5
*Not including ozone.
-67-
-------
TABLE 22
AMD TREATMENT TOTAL OPERATING COST
C/1000 Gal.
AMD FLOW, GPD
Fe , ppm
0.25 X 10
1.0 X 10
6.0 X 10
50 300 1000 50 300 1000 50 300 1000
OZONE GENERATED ON SITE-ELECTRIC DISCHARGE OZONIZERS
A. ONCE-THROUGH AIR FEED, 7.25 KW-Hr/lb
OZONE
AMD PLANT
TOTAL
OZONE
AMD PLANT
TOTAL
OZONE
AMD PLANT
TOTAL
OZONE
AMD PLANT
TOTAL
3.6
8.8
12.4
20
10
30
.1
.1
.2
61
13
74
.1
.1
.3
3.4
7.5
10.9
18
8
27
.1
.9
.0
55
12
67
.0
.2
.2
2.8
6.9
9.7
16.0
8.3
24.3
B. ONCE-THROUGH AIR FEED. 9.75 KW-Hr/lb
4.2 24.8
8.8 10.1
13.0 34.9
75.3
13.1
4.2 22.2
7.5 8.9
67.9
12.2
3.7 19.6
6.9 8.3
88.4 11.7 31.1 80.1 10.6 27.9
C. OXYGEN FEED WITH RECYCLE, 3.75 KW-Hr/lb
4.9 21.2
8.8 10.1
56.5
13.1
3.7 16.5
7.5 8.9
13.7 31.3 69.6 11.2 25.4
45.7
12.2
57.9
2.7 12.6
6.9 8.3
9.6 20.9
D. OXYGEN FEED WITH RECYCLE, 5.0 KW-Hr/lb
5.5 24.1
8.8 10.1
14.3 34.2
65.2
13.1
4.3 19.1
7.5 8.9
52.9
12.2
3 . 2 14 . 5
6.9 8.3
78.3 11.8 28.0 65.1 10.1 22.8
51.7
11.5
63.2
62.5
11.5
74.0
35.8
11.5
47.3
42.1
11.5
53.6
-68-
-------
TABLE 23
OZONE GENERATED IN 40 TON/DAY CENTRAL PLANT, SHIPPED TO AMD SITE
C/1000 Gal.
AMD PLOW, GPD
++, ppm
0
50
.25 X
300
A. ELECTRIC DISCHARGE
1. 5
OZONE
AMD PLANT
DISTRIBUTION
LABOR
TOTAL
2. 6
OZONE
AMD PLANT
DISTRIBUTION
LABOR
TOTAL
io6
1000
1.
50
OZONIZERS,
MIL./KW-Hr POWER
1.2
8.8
0.9
2.0
12.9
7.0
10.1
5.4
2.0
24.5
23
13
14
2
52
MIL./KW-Hr POWER
1.5
8.8
0.9
2.0
13.2
B . CHEMONUCLEAR
I. G
OZONE
AMD PLANT
DISTRIBUTION
LABOR
TOTAL
2. G
OZONE
AMD PLANT
DISTRIBUTION
LABOR
TOTAL
= 15, E
1.0
8.8
0.9
2.0
12.7
= 10, E
1.3
8.8
0.9
2.0
13.0
8.0
10.1
5.4
2.0
25.5
OZONE
= 0.
5.8
10.1
5.4
2.0
23.3
= 0.
6.8
10.1
5.4
2.0
24.3
26
13
14
2
55
0 X
300
io6
1000
RECYCLED
on
2
6
50
.0 X
300
io6
1000
, 5 KW-Hr/lb
COST
.3
.1
.0
.0
.4
1.2
7.5
0.9
1.0
10.6
7.0
8.9
5.4
1.0
22.3
23
12
14
1
50
.3
.2
.0
.0
.5
1.2
6.9
0.9
0.5
9.5
7.0
8.3
5.4
0.5
21.2
23.3
11.5
14.0
0.5
49.3
COST
.0
.1
.0
.0
.1
1.5
7.5
0.9
1.0
10.9
, RECYCLED O
20
19
13
14
2
48
20
22
13
14
2
51
.5
.1
.0
.0
.6
.5
.1
.0
.0
.6
1.0
7.5
0.9
1.0
10.4
1.3
7.5
0.9
1.0
10.7
8.0
8.9
5.4
1.0
23.3
5.8
8.9
5.4
1.0
21.1
6.8
8.9
5.4
1.0
22.1
26
12
14
1
53
19
12
14
1
46
22
12
14
1
49
.0
.2
.0
.0
.2
.5
.2
.0
.0
.7
.5
.2
.0
.0
.7
1.5
6.9
0.9
0.5
9.8
1.0
6.9
0.9
0.5
9.3
1.3
6-. 9
0.9
0.5
9.6
8.0
8.3
5.4
0.5
22.2
5.8
8.3
5.4
0.5
20.0
6.8
8.3
5.4
0.5
21.0
26.0
11.5
14.0
0.5
52.0
19.5
11.5
14.0
0.5
45.5
22.5
11.5
14.0
0.5
48.5
-69-
-------
TABLE 24
OZONE GENERATED IN 200 TON/DAY CENTRAL PLANT. SHIPPED TO AMD SITE
C/1000 Gal.
AMD FLOW, GPD
Fe , ppm
0.25 X
50 300
A. ELECTRIC DISCHARGE
1. 5
OZONE
AMD PLANT
DISTRIBUTION
LABOR
TOTAL
2. 6
OZONE
AMD PLANT
DISTRIBUTION
LABOR
TOTAL
MIL.
1
8
0
2
12
MIL.
1
8
0
2
12
/KW-HR
.1 6.4
.8 10.1
.9 5.4
.0 2.0
.8 23.9
io6
1000
1.
50
OZONIZERS ,
POWER
21.3
13.1
14.0
2.0
50.4
/KW-HR POWER
.2 7.2
.8 10.1
.9 5.4
.0 2.0
.9 24.7
B. CHEMONUCLEAR OZONE
1. G
OZONE
AMD PLANT
DISTRIBUTION
LABOR
TOTAL
2. G
OZONE
AMD PLANT
DISTRIBUTION
LABOR
TOTAL
= 15
0
8
0
2
12
= 10
0
8
0
2
12
, E = 0
.7 4.1
.8 10.1
.9 5.4
.0 2.0
.4 21.6
, E = 0
.9 5.2
.8 10.1
.9 5.4
.0 2.0
.6 22.7
24.0
13.1
14.0
2.0
53.1
COST
1.1
7.5
0.9
1.0
10.5
COST
1.2
7.5
0.9
1.0
10.6
, RECYCLED O
.20
13.7
13.1
14.0
2.0
42.8
.20
17.3
13.1
14.0
2.0
46.4
0.7
7.5
0.9
1.0
10.1
0.9
7.5
0.9
1.0
10.3
0 X
300
io6
1000
RECYCLED
6.4
8.9
5.4
1.0
21.7
7.2
8.9
5.4
1.0
22.5
4.1
8.9
5.4
1.0
19.4
5.2
8.9
5.4
1.0
20.5
21
12
14
1
48
24
12
14
1
51
13
12
14
1
40
17
12
14
1
44
°i'
2.
.3
.2
.0
.0
.5
.0
.2
.0
.0
.2
.7
.2
.0
.0
.9
.3
.2
.0
.0
.5
6
50
.0 X
300
io6
1000
, 5 KW-Hr/lb
1
.1
6.9
0
0
9
1
6
0
0
9
0
6
0
0
9
0
6
0
0
9
.9
.5
.4
.2
.9
.9
.5
.5
.7
.9
.9
.5
.0
.9
.9
.9
.5
.2
6.4
8.3
5.4
0.5
20.6
7.2
8.3
5.4
0.5
21.4
4.1
8.3
5.4
0.5
18.3
5.2
8.3
5.4
0.5
19.4
21.3
11.5
14.0
0.5
47.3
24.0
11.5
14.0
0.5
50.0
13.7
11.5
14.0
0.5
39.7
17.3
11.5
14.0
0.5
43.3
-70-
-------
r
T
80
70
60
50
40
•
< 30
o
8 20
o
10
ON-SITE OZONE GENERATION
RECYCLED OXYGEN FEED
0.25xlO°GPD
1.0 x!0°GPD J
6.0 xlO"GPD -I
3.75 KW-HR/LB
5.0 KW-HR/LB
o
I
(S)
a
o
0
uj 90
ON-SITE OZONE GENERATION
ONCE-THROUGH AIR FEED
200 400 600 800 1000
Fe*+ CONTENT-ppm
TOTAL AMD TREATMENT COSTS USING OZONE
ELECTRIC DISCHARGE OZONIZERS
FIGURE 20
-71-
-------
10
60
50
40
< 30
O
O
i
I-
(S)
a
o
i-
z
LJ
S 60
or
1 50
40
30
20
10
0
0.25^ 6
l.Q Ul06GPD
J
GPD_
OZONE CAPACITY-40TON/DAY
6MIL/KW-HR POWER -
5MIL/KW-HR POWER
xlO GPD
OZONE CAPACITY-200 TON/DAY
6MIL/KW-HR POWER
5MIL/KW-HR POWER
200
400 600 800 1000
Fe++CONTENT-ppm
TOTAL AMD TREATMENT COST USING ELECTRIC-DISCHARGE OZONE
CENTRAL PLANT OZONE GENERATION.SHIPPED TO AMD SITE
5KW-HR/LB 03 POWER CONSUMPTION
FIGURE 21
-72-
-------
60
50
40
J 30
o
o 20
o
^ 10
o
^- o
<
UJ
cr
50
Q
5 40 h-
<
0.25
°-25 I 6 -I
.0 J-xlO GPiP
-6.0
OZONE CAPACITY-40 TON/DAY
G = IO, E=0.20
G = I5,E = 0.20
-0.25
lOGPD
OZONE CAPACITY-200 TON/DAY
G = IO,E=0.20
G=I5,E=0.20
0 200 400 600 800 1000
Fe*+ CONTENT-ppm
TOTAL AMD TREATMENT COST USING CHEMONUCLEAR OZONE
CENTRAL PLANT OZONE GENERATION, SHIPPED TO AMD SITE
FIGURE 22
-73-
-------
TABLE 25
TOTAL INVESTMENT COSTS FOR AMD TREATMENT
USING ON-SITE OZONE WITH RECYCLED OXYGEN FEED
5.0 KWH/LB OZONE
COSTS IN THOUSANDS OF DOLLARS
AMD FLOW,
GAL./DAY
+2
Fe CONG'N
ppm
250,000,
1,000,000
6,000,000
50 300 1000 50
300
1000
50
300 1000
OZONE PLANT
AMD PLANT
TOTAL $
14
52
60
53
66 113
190 40 220
53 156 163
530 220 810 2130
175 790 830 855
243 196 383
705 1010 1640 2985
-74-
-------
co 1000
UJ
o
h-
800
600
400 —
200 —
RECYCLED OXYGEN FEED
5.0 KWH/LB OZONE
200
I06 GAL/DAY AMD
x I06 GAL/DAY AMD
0.25 x I06 GAL/DAY AMD
400 600 800
Fe"*~ CONTENT - ppm
1000
TOTAL PLANT INVESTMENT COST FOR AMD TREATMENT
USING ON-SITE ELECTRIC DISCHARGE OZONE
FIGURE 23
-75-
-------
TABLE 26
COMPARISON OF AMD TOTAL TREATMENT COSTS
COSTS IN CENTS PER 1000 GAL.
AMD FLOW - GAL. PER DAY
0.25 X 106 1.0 X 106 6.0 X 1Q6
Fe++ CONTENT-ppm j>0 300 1000 _50 300 1000 50_ 300 1000
1. ELECTRIC DISCHARGE WITH RECYCLED OXYGEN FEED, ON-SITE OZONE GENERATION
@ 3.75 Kwh/lb. 14 31 70 11 25 58 10 21 47
@ 5.00 Kwh/lb. 14 34 78 12 28 65 10 23 54
2. ELECTRIC DISCHARGE WITH ONCE-THROUGH AIR FEED, ON SITE OZONE GENERATION
@ 7.25 Kwh/lb. 12 30 74 11 27 67 10 24 63
@ 9.25 Kwh/lb. 13 35 88 12 31 80 11 28 74
CENTRAL OZONE PLANTS WITH DISTRIBUTION SYSTEMS
3. ELECTRIC DISCHARGE, 40 TON/DAY OZONE
@> 5 mil/Kwh power 13 24 52 11 22 50 10 21 49
(i 6 mil " " 13 26 55 11 23 53 10 22 52
4. ELECTRIC DISCHARGE, 200 TON/DAY OZONE
@ 5 mil/Kwh power 13 24 50 10 22 48 9 21 47
@> 6 mil/ " " 13 25 53 11 23 51 9 21 50
5. CHEMOHUCLEAR, 40 TON/DAY OZONE
G=10, E=0.20 13 24 52 11 22 50 10 21 48
G=15, E=0.20 13 23 49 10 21 47 9 20 45
6. CHEMONUCLEAR, 200 TON/DAY OZONE
G=10, E=0.20 13 23 46 10 21 44 9 19 43
G=15, E=0.20 12 22 43 10 19 41 9 18 40
-76-
-------
plants. One might wish to ascertain the over-all desir-
ability of building central ozone generating facilities,
considering both the investment and operating costs.
Taking the southwest Pennsylvania situation of 486,000,000
gal./day AMD flow, at an average Fe+2 concentration of
about 200 ppm, the total investment cost necessary for
central ozone plants, both chemonuclear and electric
discharge, was calculated. The investment in AMD neu-
tralization facilities at the 2,160 sites was also
calculated, and these are compared with on-site ozone
generation (via electric discharge) and AMD neutraliza-
tion, as shown in Table 27. Operating costs for these
situations are also included in the breakdown. It is
seen that both investment and operating costs are lower
for central plants, whether they utilize chemonuclear
or electric discharge ozone. Note that the investment
cost for the central ozone generating plants include an
oxygen plant and the necessary storage and distribution
equipment for ozone shipment. The AMD neutralization
facilities at each site utilizing shipped ozone also
include storage equipment in their investment cost. The
on-site plant cost consists of $52,000 for neutraliza-
tion equipment and $20,000 for ozone storage. The total
over-all investment and operating costs may be consid-
ered on the high side for this situation because, in
actuality, many AMD sites would have higher flows than
this average case. As a result, investment and operat-
ing costs would both be lower. The main purpose of
presenting this data is merely to indicate the magnitude
of the costs involved and the relative merits of each
system.
Since the chemonuclear system is not a fully devel-
oped process, the additional development cost of the
process should be considered. Possibly five years of
development at a cost of $10-$15,000,000 might be re-
quired to bring this process to the point which would
permit construction of the 200-ton per day central
plant. In this light, the first cost of chemonuclear
vs. electric discharge ozone would be roughly equivalent.
However, the operating costs for the chemonuclear case
are lower than those for electric discharge; reference
to Table 27 shows the chemonuclear operating cost to be
2£ per 1000 gal. lower than electric discharge.
-77-
-------
TABLE 27
COST BREAKDOWN FOR TOTAL AMD TREATMENT
OF PENNSYLVANIA AMD STREAMS
486 MILLION GALLONS PER DAY
Investment Costs - Million Dollars
Central Central On-Site
Chemo- Elec. Elec.
nuclear Disch. Disch.
Ozone Plants 26.0
AMD Neutrali-
zation* 156.0
Total Investment 182.0
Operating
Central
Chemo-
nuclear
Depreciation-? . 3% 9.1
Nucl. Fuel Cycle 0.9
Labor 2 . 1
Power 3 . 9
Maintenance 0 . 1
Purchased Oxygen
Distribution 0.8
Limestone 1.2
Total Operating
Costs 18.1
34.8
156.0
190.8
Costs -
99.5
113.0
212.5
C/1000 Gal.
Central On-Site
Elec.
Disch
9.6
-
2.1
6.3
0.1
-
0.8
1.2
20.1
Elec.
Disch.
10.6
-
1.0
7.2
1.0
5.4
-
1.2
26.4
Annual Operating
Costs $26.4x10 $29.3xl06 $38.5xl06
*
Assumes 2,160 AMD treatment sites with average flow
rates of 250,000 gpd.
-78-
-------
6.4 COMPARISON WITH PRESENT METHODS
Comparison of the ozone oxidation and neutraliza-
tion method with presently used methods is difficult
and hazardous, since a common basis for comparison
should be used, but does not exist. In particular,
one reason is that the coal industry uses costs based
on a per ton of coal mined depreciation method; this
in itself means that each mine is capitalized differ-
ently. However, Martin and Hill(3) of FWQA state
costs of neutralization can vary from 10£ to $1.30 per
thousand gal. AMD. The present study shows costs
ranging from 9-78C maximum; thus, on this basis, ozone
treatment is not out of line.
At the Third AMD Symposium in Pittsburgh, it was
stated (3 ' that a 1-million gal. per day AMD plant,
treating 150 ppm Fe++, could be built for an equipment
cost of $350,000. Using the same fixed charge rate
(7.3%) as this study, and adding appropriate lime,
labor and power costs, the AMD treatment cost for that
situation is estimated to be in the 17£ per 1000 gal.
range, as illustrated in Table 28. The estimate for ozone
treatment cost for the same case is 16£ per 1000 gal.
using on-site electric discharge ozone and limestone
treatment, and a total investment cost of $280,000.
Using ozone obtained from a chemonuclear central plant,
the treatment cost would be lowered to 13£ per 1000 gal.,
at an investment cost of $184,000. This infers that
the use of ozone permits operation at lower costs than
those presently attained. The reason is that the costs
of ozone generation equipment are of approximately the
same magnitude as the clarifier-thickeners presently
used, which are large, costly pieces of equipment. Also,
the ozone process offers the benefit of permitting the
use of limestone, at $5 per ton, over lime which costs
$17-$18 per ton.
-79-
-------
TABLE 28
COST OF CONVENTIONAL AMD TREATMENT
BASIS: 1 MILLION GAL./DAY AMD
+2
Fe CONTENT =150 ppm.
INVESTMENT = $350,000
@ 7.3% FIXED CHARGE RATE = 8.6C/1000 GAL.
OPERATING COST C/1000 GAL.
DEPRECIATION
LIME @>$18/TON
POWER
LABOR
8.6
4.2
3.3
1.0
TOTAL
17.1C/1000 GAL.
-80-
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7. DISCUSSION
The benefits of ozone usage are seen as follows.
Ozone permits rapid and efficient oxidation of Fe+2
in acid media. Process control becomes much simpler,
because the close control required in the present pro-
cess, which uses lime, is not required. Because the
oxidation can proceed at low pH, neutralization can
stop at pH 7, thus reducing limestone requirements
and sludge handling, whereas at present the pH must
be brought above 8.0 for effective oxidation using
air. The high reactivity of ozone results in a higher
oxidation rate, increasing the throughput available
for a given investment, and decreasing the investment
required for land for holdup ponds. Limestone also
results in higher sludge density and faster settling
times; this again reduces settling" pond requirements,
fluid handling equipment, and ultimate disposal
problems.
The problem of sludge disposal cannot be covered
here, since each AMD site has its own peculiarities.
Some sites have worked out mines and bore-holes avail-
able for sludge disposal, and others require that the
sludge be pumped over relatively large distances for
disposal. In some cases, the sludge is actually
trucked to a disposal point. Therefore, it is impos-
sible to speculate about disposal costs. However, the
anticipated higher sludge density and lower water con-
tent of the sludge should result in an appreciable
cost reduction for disposal.
As a result of this study, which shows favorable
economic feasibility, it is recommended that the pro-
posal (^^ originally submitted to the Commonwealth of
Pennsylvania Bureau of Mines and FWQA for "Treatment
of Acid Mine Drainage by Ozone Oxidation," which
called for a mobile demonstration plant to evaluate
the field practicability of the process, be constructed
and operated. This would permit obtaining the required
data on oxidation rates, sludge density and settling
rates, and actual operating costs. Although chemo-
nuclear ozone is more economical in the long term, the
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demonstration system should employ electric-discharge
ozone because the small unit required is readily
available. The investigation of new and improved
methods of ozone production should also be pursued.
Based on the results of the field study, a firm
decision could be made regarding the potential bene-
fits of ozone treatment. It may then be desirable
to enter into a small development program for central
plant ozone production and shipping, which offers
distinct economic advantages for high-flow, high iron
AMD streams.
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ACKNOWLEDGEMENT
The authors of this report are:
M. Beller
C. Waide
M. Steinberg
Department of Applied Science
Brookhaven National Laboratory
Upton, New York 11973
The authors acknowledge the contribution of Dr. J.R.
Powell for Appendix A on the Electric Field-Radiation
Ozonizer, and also the review and suggestions made by
Mr. B. Manowitz of the Department of Applied Science,
Brookhaven National Laboratory, and Dr. J.M. Shackelford
of the Environmental Protection Agency.
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REFERENCES
1. E. A. Zawadzki, Acid Mine Drainage Research at
Bituminus Coal Research, Inc. Presented at
AIME Meeting, Las Vegais, Nevada, (September 8,
1967).
2. States Make Headway on Mine Drainage, Environ-
mental Science and Technology. Vol. 3, No. 12,
1237-9, (December 1969) .
3. Second Symposium on Coal Mine Drainage Research,
Sponsored by the Ohio River Valley Water Sanita-
tion Commission, Pittsburgh, Pa., (May 1968).
4. Third Symposium on Coal Mine Drainage Research,
Sponsored by the Ohio River Valley Water Sanita-
tion Commission, Pittsburgh, Pa., (May 19-20,
1970).
5. W. Stumm, G. F. Lee, Ind. Eng. Chem., Vol. 53,
No. 2, p. 143-6 (February 1961).
6. R. B. Rozelle, et al, Studies on the Removal of
Iron from Acid Mine Drainage Water, Wilkes
College Research and Graduate Center. Submitted
to Coal Research Board, Commonwealth of Pennsyl-
vania, (June 1968).
7. E. A. Mihok, M. Deuhl, C. E. Chamberlain and
J. G. Selmeczi, Mine Water Research: The Lime-
stone Neutralization Process, Report of Investi-
gations, U. S. Bureau of Mines, Department of
the Interior.
8. S. Sideman, 0. Hortascsu and J- W. Fulton, Mass
Transfer in Gas-Liquid Contacting Systems, Ind.
& Eng. Chem. 58, No. 7, p. 32-47, (July 1966).
9. R. H. Perry, C. H. Chilton and S. D. Kirkpatrick,
Chemical Engineers Handbook, Section 18, McGraw
Hill, (1963).
-84-
-------
10. F. Yoshida, A. Ikeda, S. Imakawa and Y. Miura,
Oxygen Absorption Rates in Stirred Gas-Liquid
Contractors, Ind. Eng. Chem. 52, No. 5, 435-438,
(May 1960).
11. M. Steinberg, J. Pruzansky, L. R. Jefferson and
B. Manowitz, Removal of Iron from Mine Drainage
Waste with the Aid of High-Energy Radiation,
Part I, Brookhaven National Laboratory Report
No. 11576, (July 1967); Part II, BNL No. 12114,
(Dec. 1967); Part III, BNL No. 12115, (Jan. 1968).
12. Matheson Gas Data Book, 4th Ed., The Matheson Co.,
Inc. (1966).
13. S. C. Lind, Radiation Chemistry of Gases, 83-86,
Reinhold, New York, (1961).
14. D. W. Wall and L. A. Brown, J. Phys. Chem. 65,
915-919 (1961).
15. J. F. Kircher, J. S. McNutley, J. L. McFarling
and A. Levy, Radiation Research 1^3, 452-65, (1960) .
16. G. R. A. Johnson and J. M. Warman, Discussions,
Faraday Society, 37, 87-95, (1964).
17. J. T- Sears and J. W. Sutherland, Nuclear Appli-
cations 2_, 62-3, (1968).
18. Z. I. Kertesz and G. F. Parsons, Science 142,
1289-90, (1963).
19. L. N. Less and A. J. Swallow, Nucleonics 22, No. 9,
58-61, (1964).
20. J. Shah and E. C. Maxie, Intern. J. Appl. Radiation
Isotopes, 17, 155-9, (1966).
21. M. Steinberg, "03 and N02 Formation by Irradiation
of a N2-02 Gas Mixture in a Flowing System at
Elevated Pressures," BNL 50017, Brookhaven National
Laboratory, Upton, N.Y., (Sept. 1966).
-85-
-------
22. R. N. Dietz, J. D. Smith, M. Steinberg, (to be
presented at Am. Chem. Soc. Meeting, New York,
September 7-12, 1969).
23. J. A. Ghormley, C. J. Hochanadel and J. W. Boyle,
J. Chem. Phys. 50, 419-23, (1969).
24. M. Steinberg, W. D. Tucker, C. Waide, M. Beller.
P. Bezler,and B. Manowitz, "Safety Review of
the Brookhaven Chemonuclear In-Pile Research
Loop," BNL 13001, Brookhaven National Laboratory,
Upton, N.Y. (Oct. 1968).
25. M. Steinberg, W. D. Tucker and G. Farber, Fis-
sion Fragment Recoil Energy Source and Chemo-
nuclear Fuel Element, Am. Nucl. Soc. Trans. 10,
44, (June 1967).
26. M. Steinberg, Chem. Eng. Progress 62, No. 9,
195-16, (1966).
27. M. Beller, Internal Reports, Brookhaven National
Laboratory. (Dec. 1968 - May 1969).
28. J. T. Sears and J. W. Sutherland, J. Phys. Chem.
72, 1166-71, (1968).
29. M. Steinberg, "The Recovery of Fission Product
Xenon and Krypton by Absorption Processes,"
Brookhaven National Laboratory, BNL 542 (Jan.
1959).
30. J. R. Merriman, et al., "Concentration and Collec-
tion of Krypton and Xenon by Selective Absorption
in Fluorocarbon Solvents," SM-110/25 (K-L-6198),
Intl. Atomic Energy Agency Conference at Harvard
University, Cambridge, Mass. (Aug. 1968) .
31. Kirk-Othmer, "Encyclopedia of Chemical Technology,1
Vol. 14, 410-32, 2nd Ed., Interscience Publishers,
(1967) .
32. Technical Bulletin No.201, Welsbach Corp.,
Philadelphia, Pa., (1968).
-86-
-------
33. c. McGuire, The Linde Co., Div. Union Carbide,
Private communication (June 1970) .
34. R. A. Tybout, "A Cost-Benefit Analysis of Mine
Drainage," Second Symposium of Coal Mine Drainage
Research, Pittsburgh, Pa., (1968).
35. G. F. Haines, Jr., Personal Communication,
(May 19, 1970).
36. Proposal on Treatment of Acid Mine Drainage by
Ozone Oxidation, Brookhaven National Laboratory,
Upton, N.Y., submitted to the Commonwealth of
Pennsylvania Bureau of Mines and the FWQA
(Nov. 1968, Rev- Feb. 1969).
37. Operation Yellowboy, Dow-Oliver, Inc., Stamford,
Conn., (June 1966).
38. Oxygenation of Ferrous Iron, Harvard University,
FWQA Report No. 14010, (June 1970).
39. Studies on Limestone Treatment of Acid Mine
Drainage, Bitum. Coal Res., Inc., FWQA Report
No. DAST-33, 14010 EIZ (Jan. 1970).
40. R. D. Hill and R. C. Wilmoth, Limestone Treat-
ment of Acid Mine Drainage, FWQA Report No. 14010
(Oct. 1970) .
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APPENDIX A
The Combined Electric Field-Radiation Ozonizer
Conventional ozonizers have low chemical effic-
iency (8%) and low power density (~0.03 W/cm3 at 60
cps). Further, they must operate with a small dis-
charge gap (2 to 4 mm). The low power density and
small gap cause a very high capital cost for the
ozonizer. For example, a 600-ton/day ozone plant
would require almost 30 million square feet of ozon-
izer surface (at 60 cps). This could be reduced by
almost a factor of 100 by operating to higher fre-
quencies (6000 cps), but a tremendous area would still
be required. At 6000 cps, a 600-ton/day plant would
require ~60 miles of 4-in.-diam ozonizers. (The dis-
charge area varies inversely as frequency, but the
discharge gap remains fixed.) Such a plant is imprac-
tically large.
The low power density and small gap of the con-
ventional ozonizer are the result of the requirement
that electrons in the gap be created by the electric
field. To prevent arcing, a high resistance barrier
(e.g., glass) is placed between the electrodes. This
acts like a large resistance in series with the capa-
citance of the electrodes, and quenches the discharge.
Considerable electrical energy is dissipated in the
glass, lowering the efficiency. The power density is
kept low since the charge produced in the corona
streamer from the instantaneous cathode takes some
time to leak through the glass, and a new streamer can-
not be established until it does. The chemical effic-
iency of the ozonizer decreases with increasing gap,
because the discharge tends to be more localized, with
coarse, hot sparks. With very small gaps, the discharge
is finer and more uniform. Ozone tends to be destroyed
in hot spark channels. For example, for gaps of 0 to 2
mm, the ozone yield is ~200 gAWh, but drop to ~100 gA
Wh for gaps of 3 to 4 mm. Thus, though higher frequen-
cies can increase power density, the discharge gap must
remain fixed.
If the ionization process were independent of the
electric field, ozonizers could operate with higher
A-l
-------
efficiency, greater power density, and larger discharge
gaps. The glass barrier in the ozonizer would no longer
be necessary, since there would be no possibility of
breakdown and arcing.
Radiation can provide ionization independent of the
electric field. The radiation power would be a small
fraction (e.g., 0.01 to 0.1%) of the electric field
power, so the cost of the radiation would be low. This
permits an electrochemical discharge that has much
greater versatility than the conventional corona dis-
charge (ozonizer), with a number of significant advan-
tages:
1. The electron concentration and discharge power
are controlled by the radiation intensity-
2. The discharge is spatially uniform, with no
tendency to arc.
3. Discharge power can be much greater than that
of a conventional discharge.
4. The electron energy in the conventional corona
discharge is set by the condition that it be sufficient
to generate additional electrons by electron-molecular
conditions. This energy may not be the most favorable
one for a given chemical reaction. In the electrochmi-
cal discharge, since the electrons are not produced by
the electric field, the electron energy can be much less
than it is in the corona discharge, and in fact, can be
controlled by electric field strength. Thus, optimum
electron energy can be selected for any process.
5. The time scale of the discharge can be con-
trolled by the radiation source; that is, a short pulse
of radiation could cause a very fast discharge. The
radiation is then shut off, and the radicals produced
react. This type of discharge may be more efficient
than a continuous discharge.
The electrochemical discharge proposed here is a
new type of chemical process. It has many other possible
uses besides ozone production, for example, it may be
A-2
-------
useful for NO synthesis, hydrazine production from
ammonia, coal hydrogenation, acetylene production,
and various organic reactions which cannot be carried
out in a conventional corona discharge.
The electrochemical discharge can work at dc,
low frequency, or high frequency. At dc or low fre-
quency it is significantly better than the ozonizer
but space charge effects limit its power density
(~1 W/cm3) and discharge gap (~10 mm)„ At high fre-
quency, much larger discharge gaps and power densities
are possible.
Researchers have worked with radiofrequency ozon-
izer s and found very low chemical efficiencies (1% of
conventional ozonizers). However, the condition that
the electric field generates the electrons is the cause
of this low efficiency- The ion density is so high
that the plasma simply polarizes with a large part of
the applied voltage appearing in a very thin sheath
next to the cathode. Because the sheath is so thin,
most of the discharge region is not effective in pro-
ducing ozone.
If the ionization process is independent of elec-
tric field, the discharge can be uniform throughout
the gap, and the chemical efficiency will be of the
same order as that of the dc or low frequency units.
However, the power density will be much greater
(~50 W/cm3) and the discharge gap can be considerably
larger (e.g., 150 mm).
The projected operating characteristics of a
radiofrequency electrochemical discharge are as
follows:
Unit Size: 15 cm discharge gap
30 cm wide
120 cm long
RF Power;
Power density 36 W/cm (rms)
Frequency 20 MHz
Voltage (peak) 132,000 V
Total power 1.95 MW
A-3
-------
Gas:
Oo concentration (exit)
Flow velocity
Static density
Tons/day of 63
Chemical efficiency
0.6%
1670 ft/sec (M=1.6)
-0.33 p
10 °
16% (assumed equal to
220 g/kWh, best
efficiency in
conventional
ionizer)
Radiation Power:
Radiation input power
to gap
3 kw (assumes n /n_ -
„„_?, e O0
An ozone plant with a total production of 600 tons/
day would require just 60 of the proposed ozonizers,
and 113 MW(e) of electric power. The capital cost of
the ozonizers, including power conversion equipment,
would be on the order of $100/kW or ~10 million for
the entire plant (not including contractors, 02 prep-
aration, and compressors).
The data on which these calculations were based
are reasonably good. The principal uncertainty is the
detachment rates of electrons from O~, 02", and whether
03" is important. If the electron detachment frequency
is controlled by the vibrational temperature of 02/ and
not the translational temperature, then the estimated
detachment rates should be sufficient to make the pro-
cess go. There is strong indication that this is so in
microwave afterglow experiments with ©2 -
We plan to make measurements of the attachment
and detachment rates for electrons to form various
negative ions in oxygen. This can be done conveniently
with a Van de Graaff electron beam to provide the ioni-
zation in an experimental cell. Both dc and rf electric
fields will be used, and the O3 concentrations measured
in situ spectrophotometrically.
A-4
-------
BIBLIOGRAPHIC:
Brookhavcn National Laboratory, Treatment of Acid Mine Drainage by O?.on
Oxidation. Final Report FWQA Contract No. 1-1-12-838, December, 1970.
ABSTRACT:
An engineering design and economic study to evaluate the feasibility of ozone
oxidation and limestone neutralization of Acid Mine Drainage (AMD) was per-
formed. The study concludes that an ozone process is feasible, compares economically
with existing processes, and offers potential advantage in process control, reduced
neutralization costs, and simplified AMD sludge handling and disposal. Ozone pro-
duction by electric discharge and radiation processes are compared both for on-site
and central plant installations utilizing ozone shipping and storage facilities. A central
chemonuclear ozone production plant with a distribution system is found to be most
economical, followed by electric discharge central and on-site plants Design and
construction of a mobile pilot plant which employs electric discharge ozonizers is
recommended for field trails of the process.
This report was prepared in fulfillment of Contract No. 14-.12-838 between the
Federal Water Quality Administration and Brookhaven National Laboratory.
ACCESSION NO.
KEYWORDS:
Mine Drainage
Ozone Treatment
Treatment Costs
Neutralization
Limestone
Oxidation
Ferrous Iron
Ferric Iron
BIBLIOGRAPHIC:
Brookhaven National Laboratory, Treatment of Acid Mine Drainage by Ozone
Oxidation. Final Report FWQA Contract No. 14-12-838, December, 1970.
ABSTRACT:
An engineering design and economic study to evaluate the feasibility of ozone
oxidation and limestone neutralization of Acid Mine Drainage (AMD) was per-
formed. The study concludes that an ozone process is feasible, compares economically
with existing processes, and offers potential advantage in process control, reduced
neutralization costs, and simplified AMD sludge handling and disposal. Ozone pro-
duction by electric discharge and radiation processes are compared both for on-site
and central plant installations utilizing ozone shipping and storage facilities. A central
chemonuclear ozone production plant with a distribution system is found to be most
economical, followed by electric discharge central and on-site plants Design and
construction of a mobile pilot plant which employs electric discharge ozonizers is
recommended for field trails of the process.
This report was prepared in fulfillment of Contract No. 14-12-838 between the
Federal Water Quality Administration and Brookhaven National Laboratory.
ACCESSION NO.
KEY WORDS:
Mine Drainage
Ozone Treatment
Treatment Costs
Neutralization
Limestone
Oxidation
Ferrous Iron
Ferric Iron
BIBLIOGRAPHIC:
Brookhaven National Laboratory, Treatment of Acid Mine Drainage by Ozone
Oxidation. Final Report FWQA Contract No. 14-12-838, December, 1970.
ABSTRACT:
An engineering design and economic study to evaluate the feasibility of ozone
oxidation and limestone neutralization of Acid Mine Drainage (AMD) was per-
formed. The study concludes that an ozone process is feasible, compares economically
with existing processes, and offers potential advantage in process control, reduced
neutralization costs, and simplified AMD sludge handling and disposal. Ozone pro-
duction by electric discharge and radiation processes are compared both for on-site
and central plant installations utilizing ozone shipping and storage facilities. A central
chemonuclear ozone production plant with a distribution system is found to be most
economical, foll&wed by electric discharge central and on-sitc plants. Design and
construction of a mobile pilot plant which employs electric discharge ozonizers is
recommended for field trails of the process.
This report was prepared in fulfillment of Contract No. 14-12-838 between the
Federal Water Quality Administration and Brookhaven National Laboratory
ACCESSION NO.
KEY WORDS:
Mine Drainage
Ozone Treatment
Treatment Costs
Neutralization
Limestone
Oxidation
Ferrous Iron
Ferric Iron
-------
1
<4cce.ssioii Number
5
2
Subject Field & Group
SELECTED WATER RESOURCES ABSTRACTS
INPUT TRANSACTION FORM
Urbanization
Brookhaven National Tja"borat-oi-\r
Upton, New York 11973
Title
Treatment of Acid Mine Drainage by Ozone Oxidation
1Q Authors)
M. B^ll»r
C.Waide
M.Steinberg
16
21
Project Designation
Contract No.
14-12-838
Note
22
Citation
Environmental Protection Agency
Washington, B.C. 202^2
U010FMH 12/70
Descriptors (Starred First)
Mine Drainage
Iron Oxidation
Ozone
neutrali zation
limestone
ferrous iron
ferric iron
treatment costs
25
Identifiers (Starred First)
27 Abstract ^n engineering design and economic study to evaluate the feasibility
Of ozone oxidation and limestone neutralization of Acid Mine Drainage (AMD)
was performed,, The study concludes that an ozone process is feasibile, com-
pares economically with existing processes, and offers potential advantages in
process control, reduced neutralization costs, and simplified AMD sludge hand-
ling and disposal,, Ozone production by electric discharge and radiation pro-
cesses are compared both for on-site and central plant installations utiliz-
ing ozone shipping and storage facilities. A central chemonuclear ozone pro-
duction plant with a distribution system is found to be most economical, fol-
lowed by electric discharge central and on-site plants,, Design and construction
of a mobile pilot plant which employs electric discharge ozonizers is recom-
mended for field trials of the process.
This report was prepared in fulfillment of Contract No014-12-838
between the Federal Water Quality Administration and Brookhaven National
Laboratory8
Key words: Mine drainage, ozone treatment, treatment cgsts,
limestone, oxidation, ferrous iron, ferric iron,,
neutralization.
Abstractor
M. Steinberg
Institution
Brookhaven National Laboratory
WR:'02 (REV JULY 19691
WRSIC
SEND TO: WATER RESOURCES SCIENTIFIC INFORMATION CENTER
U.S. DEPARTMENT OF THE INTERIOR
WASHINGTON. D. C. 20240
OPO: 1969-359-339
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